ORIGINAL PAPER

Neuroprotective effects of propofol, thiopental, etomidate,and midazolam in fetal rat brain in ischemia-reperfusionmodel

Ferhat Harman & Askin Esen Hasturk &

Mehmet Yaman & Turkan Arca & Kamer Kilinc &

Mustafa Fevzi Sargon & Erkan Kaptanoglu

Received: 17 March 2012 /Accepted: 18 April 2012 /Published online: 5 May 2012# Springer-Verlag 2012

AbstractPurpose The aim of this study was to investigate the neuro-protective effects of propofol, thiopental, etomidate, andmidazolam as anesthetic drugs in fetal rat brain in theischemia-reperfusion (IR) model.Methods Pregnant rats of day 19 were randomly allocatedinto eight groups. Fetal brain ischemia was induced byclamping the utero-ovarian artery bilaterally for 30 minand reperfusion was achieved by removing the clamps for60 min. In the control group, fetal rat brains were obtainedimmediately after laparotomy. In the sham group, fetal ratbrains were obtained 90min after laparotomy. In the IR group,IR procedure was performed. No treatment was given in theIR group. One milliliter intralipid solution, 40 mg/kg propofol,

3 mg/kg thiopental, 0.1 mg/kg etomidate, and 3 mg/kg mid-azolam was administered intraperitoneally in the vehiclegroup, propofol group, thiopental group, etomidate group,and midazolam group, respectively, 20 min before IR proce-dure. At the end of the reperfusion period, the whole brains ofthe fetal rats were removed for evaluation of thiobarbituricacid reactive substances and for examination by electronmicroscopy.Results According to lipid peroxidation data, all the anes-thetic drugs provide neuroprotection; however, ultrastruc-tural findings and mitochondrial scoring confirms that onlypropofol and midazolam provides a strong neuroprotectiveeffect.Conclusions Propofol and midazolam may be used to pro-tect fetal brain in case of acute fetal distress and hypoxicinjury as a first choice anesthetic drug in cesarean delivery.

Keywords Neuroprotection . Propofol . Thiopental .

Etomidate . Midazolam . Ischemia-reperfusion . Rat

Introduction

Neonatal encephalopathy is a significant problem related tointrapartum asphyxia. In spite of improvements in obstetricand neonatal care, hypoxic–ischemic brain damage withsevere neurologic disability is still a challenging problem.Although the mother is a potential target for therapeuticintervention, no effective therapeutic strategies have yet beendeveloped to counteract this condition [1, 2].

Recent investigations have made significant contributions inelucidating the molecular mechanisms of hypoxia–ischemia-induced neuronal injury. Essentially, the process initiates withneuronal energy failure, which triggers a cascade of events and

F. Harman :M. Yaman : E. Kaptanoglu (*)Department of Neurosurgery,Near East University Faculty of Medicine,Lefkosa Mersin 10, Turkeye-mail: erkankaptanoglu@gmail.com

A. E. HasturkDepartment of Neurosurgery, Ankara Oncology Training Hospital,Ankara, Turkey

T. ArcaDepartment of Medical Biology,Near East University Faculty of Medicine,Lefkosa Mersin 10, Turkey

K. KilincDepartment of Biochemistry,Hacettepe University Faculty of Medicine,Ankara, Turkey

M. F. SargonDepartment of Anatomy,Hacettepe University Faculty of Medicine,Ankara, Turkey

Childs Nerv Syst (2012) 28:1055–1062DOI 10.1007/s00381-012-1782-0

may culminate in either immediate or delayed neuronal death.Oxygen free radicals appear to play a central part in this chainof events, and mitochondria represent a target of attack [3].Nakai et al. [4] measured the mitochondrial respiratory activi-ties in neonatal rat brain to compare the influence of transientintrauterine ischemia in the preterm fetus with that in the termfetus and showed that mitochondrial activity and oxygen-derived free radicals might play a crucial role in the develop-ment of neonatal neurologic deficit.

Acute fetal distress having a potential for intrapartumasphyxia is an indication of cesarean delivery in emergencysettings. In this situation, intravenous and inhalation anes-thetics are generally preferred. Although there have beenseveral studies related to the effect of anesthetic drugs infetal brain [5, 6], there are some conflicts among theresults of clinical and experimental data on the brainstructure and function after ischemia in the presence ofanesthetic agents. We aimed in this study to investigatethe protective effect of propofol, thiopental, etomidate,and midazolam as anesthetic drugs in fetal rat brain inthe intrauterine IR model.

Materials and methods

Animals

This study was approved by the Institutional Animal Careand Use Committee of the Ankara Training Hospital inAnkara. The experiments were performed in accordancewith the Institutional Animal Care and Use Guidelines ofthe Ankara Training Hospital and all efforts were carried outto minimize the number of animals used and alleviate theirsuffering. The experiments were performed on 19-day-oldpregnant Sprague–Dawley rats (Animal Laboratory ofAnkara Training Hospital in Ankara). The rats were housedseparately at ambient temperature with a 12-h-light cycleand were allowed free access to water and food.

Experimental groups

The rats were randomly and blindly allocated into eightgroups of six rats each.

Group 1. (Control) Fetal brain tissues were taken immedi-ately after laparotomy from pregnant animals. IRwas not performed.

Group 2. (Sham) Fetal brain tissues were taken 90 minafter laparotomy from pregnant animals. IR wasnot performed.

Group 3. (IR) IR was produced by the method describedbelow. Tissue samples were taken immediatelyafter IR injury.

Group 4. (Vehicle) One milliliter of intralipid solution(containing 100 mg soybean oil, 22.5 mg glyc-erol, 12 mg egg lecithin per mL) was adminis-tered intraperitoneally 20 min before the IRinjury. Tissue samples were taken immediatelyafter IR injury.

Group 5. (Propofol) A 40-mg/kg single dose of propofol(PropoFlo 20 mL vial, Abbott Laboratories,North Chicago, III., USA) dissolved in vehiclesolution was administered intraperitoneally20 min before IR injury. Tissue samples weretaken immediately after IR injury.

Group 6. (Thiopental) A 3-mg/kg single dose of thiopental(Pental Sodyum 1 g Enjektabl Flakon, I.E Ula-gay Ilac Sanayii Turk A.S, Istanbul, Turkey) wasadministered intraperitoneally 20 min before IRinjury. Tissue samples were taken immediatelyafter IR injury.

Group 7. (Etomidate) A 0.1-mg/kg single dose of etomidate(Sigma Chemical Co., St. Louis, USA) wasadministered intraperitoneally 20 min beforeIR injury. Tissue samples were taken imme-diately after IR injury.

Group 8. (Midazolam) A 3-mg/kg single dose of midazo-lam (Dormicum 15 mg/3 mL ampule, DevaHolding AS, Istanbul, Turkey) was administeredintraperitoneally 20 min before IR injury. Tissuesamples were taken immediately after IR injury.

Animal preparation and intrauterine ischemia-reperfusion

The surgical procedure was performed under general anesthe-sia induced by intramuscular 10 mg/kg xylasine (Xylazyne,Bayer, Istanbul, Turkey) and 60 mg/kg ketamine hydrochlo-ride (Ketalar, Pfizer, Warner Lambert, Istanbul, Turkey). Afteradequate anesthesia, pregnant rats were placed in the supineposition and laparotomies were performed. Fetal ischemia wasinduced by clamping the utero-ovarian artery bilaterally for30 min. Reperfusion was achieved by removing the clampsfrom the arteries and circulation was restored for 60 minbefore sacrifice. An operating microscope was used to con-firm the complete interruption and restoration of blood flow inthe utero-ovarian arteries. Body temperature was continuouslymonitored with a rectal thermometer and maintained at 37 °Cusing a heating pad and an overhead lamp. At the end of thereperfusion period, the whole brains of the fetal rats wereremoved for the evaluation of thiobarbituric acid reactivesubstances (TBARS) and for ultrastructural analysis.

Biochemical determination of lipid peroxides

The samples obtained from each fetal rat were immediatelyfrozen and stored at −20 °C for assay of malondialdehyde.

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The lipid peroxide levels were measured as TBARS. Lipidperoxidation in fetal brain tissues was determined by themethod of Uchiyama and Mihara [7]. Tissues were homog-enized in 10 volumes (w/v) of cold phosphate buffer(pH 7.4). A total of 0.5-mL homogenate was mixed with3-mL 1 % H3PO4. After the addition of 1 mL of 0.67 %thiobarbituric acid, the mixture was heated in boiling waterfor 45 min. The color was extracted into N-butanol, and theabsorption at 532 nm was measured. Using tetramethoxy-propane as a standard, tissue lipid peroxide levels werecalculated in nanomoles per gram of wet tissue.

Sample preparation for electron microscopy

For transmission electron microscopic examination, the tis-sue samples were fixed in 2.5 % gluteraldehyde for 6 h,washed in phosphate buffer (pH 7.4), post-fixed in osmiumtetroxide in phosphate buffer (pH 7.4) for 2 h and dehy-drated in increasing concentrations of alcohol. Then thetissues were washed with propylene oxide and embeddedin epoxy-resin embedding media. Semi-thin sections ofabout 2 μm in thickness and ultra-thin sections of about60 nm in thickness were cut with a glass knife on a LKB-Nova (LKB-Produkter AB, Bromma, Sweden) ultramicro-tome. The semi-thin sections were stained with methyleneblue and examined by a Nikon Optiphot (Nikon Corpora-tion, Tokyo, Japan) light microscope. Following this exam-ination, the tissue blocks were trimmed, their ultra-thinsections were taken by the same ultramicrotome and theywere stained with uranyl acetate and lead citrate. Followingstaining, all the ultra-thin sections were examined by JeolJEM 1200 EX (Jeol Ltd., Tokyo, Japan) transmission elec-tron microscope. The electron micrographs were taken bythe same electron microscope.

Electron microscopic evaluation

Ultrastructural changes as the number and structure of intra-cytoplasmic organelles of neurons were assessed with theelectron microscopy (EM). We used a grading system toperform a quantitative evaluation, and an investigatorblinded to the study protocol examined the tissues. Thesystem was based on the method similar to that used forevaluating spinal cord tissue (Table 1) [8, 9]. For eachgroup, the mean scores of mitochondrial damage and stan-dard errors were calculated. Higher values were associatedwith increased severity of mitochondrial damage.

Statistical analysis

Data was expressed as the mean±SE. Non-parametric testwas chosen to analyze the EM and TBARS data because thedata distribution was not normal for at least one of the

groups. The EM and TBARS values were analyzed usingKruskal–Wallis analysis of variance. When there was asignificant difference between the groups for each assay,Mann–Whitney U test was used for post hoc for pairwisecomparisons between groups within that assay. P<0.05 wasconsidered statistically significant.

Results

TBARS

Figure 1 shows the TBARS values of fetal rat brain samplesin the control, sham, IR, vehicle, propofol, thiopental, eto-midate, and midazolam groups. The TBARS values of IRgroup were significantly higher than that of the controlgroup (p<0.001). The TBARS values of vehicle, propofol,thiopental, etomidate, midazolam groups were significantlylower than that of the IR group (p<0.05 for vehicle group,p<0.01 for propofol group, p<0.001 for thiopental andetomidate groups, and p<0.01 for midazolam group). TheTBARS value of propofol group was significantly lowerthan that of the vehicle group (p<0.01). The TBARS valueof thiopental group was significantly lower than that ofpropofol groups (p<0.05). The control and sham groupswere comparable with regard to the TBARS value.

Ultrastructural findings

Figure 2 presents representative photos obtained by thetransmission electron microscopic examination of the tissuesamples of the study groups. Figures 2a, b present thephotos of normal ultrastructural findings in the control andsham groups. In the photos of IR group (Fig. 2c), a decreasewas observed in the amount of intracytoplasmic organellesof neurons. Additionally, many large vacuoles and swollenmitochondria were present inside the cytoplasm of theseneurons. Nearly all of the mitochondria in this groupshowed ultrastructural pathological changes and most ofthem were swollen. Intercellular edema was the other

Table 1 Grading sys-tem for quantitativeevaluation of ultrastruc-tural mitochondrialfindings

Scoringparameter

Mitochondrialfindings

0 Ultrastructurally normalmitochondrion

1 Mitochondrion withprominent cristae

2 Mitochondrion withcloudy swelling

3 Amorphous materialcollection inside themitochondrion

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finding in this group. In the ultrastructural examination ofthe nuclei, cell membranes, and other organelles of theneurons, no ultrastructural pathology was detected. In thevehicle group (Fig. 2d), intercellular edema was present inbetween the neurons. Intracytoplasmic vacuoles and swollenmitochondria were seen in these neurons. After the compar-ison of the degree of ultrastructural pathological changes ofthe vehicle and IR groups, the vehicle caused less damage inthe mitochondrial structure. The only ultrastructural patho-logical finding of the propofol group (Fig. 2e) was observedin the mitochondria. There were mitochondria with promi-nent cristae. All of the ultrastructural pathological findingsof the thiopental and IR groups were similar (Fig. 2f). Theultrastructural pathological findings of the etomidate andvehicle groups were considerably similar (Fig. 2g). Therewere intracytoplasmic vacuoles and swollen mitochondria inthe neurons. Additionally, intercellular edema was detected inbetween the neurons. In midazolam group (Fig. 2h), smallareas of intercellular edema were present in between theneurons. Intracytoplasmic vacuoles and swollen mitochondriawere seen in these neurons. The midazolam group had lessultrastructural changes compared to the IR group.

Evaluation of mitochondrial scores

Figure 3 shows the mitochondrial scores in the control, sham,IR, vehicle, propofol, thiopental, etomidate, and midazolamgroups. The mitochondrial scores of the IR were significantlyhigher than that of the control group (p<0.001). The mito-chondrial scores of the propofol and midazolam groups weresignificantly lower than that of the IR group (p<0.001 andp<0.01, respectively). The mitochondrial scores of propofolgroup were significantly lower than that of the vehiclegroup (p<0.001). The mitochondrial scores of propofol

group were significantly lower than that of the midazolamgroup (p<0.001). The control and sham groups were similarwith regard to the mitochondrial scores.

Discussion

Maternal uterine artery ligation has frequently been used tostudy the consequences of reduced uterine blood flow on thefetus. This procedure has been shown to produce fetal hypox-ia, hypercapnia, and acidosis, which likely affect fetal cellularmetabolism [10]. IR is known to cause brain damage byactivating a cascade of biochemical events. It has been estab-lished that excitatory amino acids, intracellular Ca2+, oxygenfree radicals, nitric oxide (NO), apoptosis, and inflammatoryreactions play a crucial role in cell damage after perinatal IRinjury [11–13]. In the present study, IR injury was producedby uterine artery ligation since it was a suitable procedure forthe purpose of this study. The protective effect of propofol,thiopental, etomidate, and midazolam as anesthetic drugs infetal rat brain in the IR model was evaluated by measurementof lipid peroxidation and mitochondrial damage.

Increased generation of reactive oxygen species (ROS) isimplicated in the pathogenesis of many diseases and in thetoxicity of a wide range of compounds [14]. Brain tissue isrich in polyunsaturated lipids, has high iron content, and iscritically dependent on aerobic metabolism and thus highlyvulnerable to ROS-mediated oxidative damage [15]. Recentinvestigations have made significant contributions in eluci-dating the molecular mechanisms of hypoxia–ischemia-induced neuronal injury. Essentially, the process initiates withneuronal energy failure, which triggers a cascade of eventsand may culminate in either immediate or delayed neuronaldeath. Oxygen free radicals appear to play a central part in this

Fig. 1 TBARS values of fetalrat brain in control, sham, IR,vehicle, and drug-treatedgroups. Data were expressed asmean±SE. Data were comparedwith Kruskal–Wallis ANOVAwith post hoc Mann–Whitneytest. Asterisk representscomparison relative to thecontrol, plus sign representscomparison relative to theIR injury group, and hashrepresents pairwise comparisonbetween shown groups.*** or +++ or ### for p<0.001;** or ++ or ## for p<0.01;* or + or # for p<0.05

1058 Childs Nerv Syst (2012) 28:1055–1062

chain of events, and mitochondria represent a target of attack[3]. Nakai et al. [4] showed that mitochondrial activity andoxygen-derived free radicals might play a crucial role in thedevelopment of neonatal neurologic deficit. We found that theTBARS values of control and sham groups were similar;however, IR considerably increased the lipid peroxidation.These findings suggest that intrauterine IR model used in thiswork has been effective in causing significant oxidative dam-age in the present study.

The mechanisms leading to mitochondrial damage arenot known, but there are several possibilities. One is that

ischemia and recirculation lead to calcium uptake by cellsand mitochondria [16]. The accumulation of massiveamounts of calcium in mitochondria is potentially detrimen-tal. Ionized calcium can trigger degradation of the lipidskeleton of mitochondrial membranes and cause a cascadeof events, including accumulation of arachidonic acid andits breakdown products [17]. In this study, we measuredlipid peroxidation in the fetal cerebral tissues and analyzedthe mitochondrial ultrastructure as indicator of neural dam-age. We found that the mitochondrial scores of the control andsham groups were comparable. IR group had considerably

Fig. 2 Transmission electronmicroscopy of tissue samplesshows a (control group)ultrastructurally normalneurons, b (sham group)ultrastructurally normal neuronsand normal mitochondria(arrows); (c) (IR group) adecrease in the amount ofintracytoplasmic organelles,intercellular edema, andswollen mitochondria(arrows); (d) (vehicle group)intracytoplasmic vacuoles,intercellular edema, andswollen mitochondria(arrows); (e) (propofol group)ultrastructurally normalmitochondria and mitochondriawith prominent cristae(arrows); in this group, the onlyultrastructural pathology wasthe mild degree of swelling insome of the mitochondria; (f)(thiopental group) intercellularedema, an intracytoplasmicvacuole, and swollenmitochondria (arrows);(g) (etomidate group)intracytoplasmic vacuoles,intercellular edema, and amitochondrion with prominentcristae (arrow); and (h)(midazolam group) intercellularedema (e), intracytoplasmicvacuoles (v) and swollenmitochondria (arrows).Original magnification: ×6,000,bar01 μm a: ultrastructurallynormal myelinated axon; e:intercellular edema; n: nucleusof neuron; v: intracytoplasmicvacuoles; and m: normalmitochondria

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increased the mitochondrial score compared to these groups.These findings suggested that intrauterine IR model used inthis experiment generated significant damage in mitochon-dria. These quantitative results are well correlated with qual-itative findings of ultrastructural analysis. The grading systemfor quantitative assessment of ultrastructural mitochondrialchanges in the fetal brain was developed based on the modi-fication of the technique from the study of Kaptanoglu et al.[8] and was used for the first time in this work.

The vehicle solution of propofol consisting of soybean hadalso significantly decreased in the TBARS values of the fetalrat brain in our study; however, it had no significant effect onthe mitochondrial scores. Bansal et al. [18] examined whetherdietary supplementation with soybean improved the cognitivefunction of mice. They found that the TBARS levels weredecreased after soybean supplementation. That result is inaccordance with our findings and the decrease in TBARScan be explained as related to the antioxidant effect of thevehicle solution.

Propofol is an intravenous anesthetic used for manysurgical procedures. Recently, increasing evidence has sup-ported that propofol may provide a potentially beneficialrole in the prevention of neuronal injury in experimentalstudies. The neuroprotective properties of propofol may berelated to the reduction in cerebral metabolism, potentiationof gama-aminobutyric acid receptors, altered cerebral bloodflow, and its antioxidant ability [9, 19–21]. It has beenshown that maternal treatment with propofol had a neuro-protective effect on the fetal rat brain after intrauterine IRinjury [8, 22, 23]. Propofol may inhibit lipid peroxidation byits inhibitory effect on excitotoxicity and/or its direct freeradical scavenging effect in vivo, and propofol might have arole in the induction of anesthesia for cesarean deliveryespecially in the presence of intrapartum asphyxia [23].

We found that propofol decreased both the TBARS leveland mitochondrial score. Our findings support that propofolhas neuroprotective effect by preventing lipid peroxidationand, this is well correlated with previous work [8, 22, 23].Our results also suggest that propofol is the most protectivedrug on the mitochondrial damage when compared with theother study drugs. Ultrastructural findings also showed thatthere was a general improvement at the cellular level inpropofol-treated rats. According to findings of our study,propofol and vehicle solution decreased lipid peroxidationalthough propofol caused more decrease compared to thevehicle solution. Only propofol but not the vehicle solutioncould decrease mitochondrial damage. Our results suggestthat propofol alone has neuroprotective effect. Thus propo-fol may be the first choice in emergency cesarean setting forpreventing fetal brain ischemia.

Thiopental, an ultra-short-acting barbiturate, has beenused for anesthetic induction because of its rapid onset andshort duration of action. It has been reported that thiopentaldepresses the release of ROS from neutrophils and inhibitslipid peroxidation as antioxidant properties [24, 25]. Thio-pental is also primarily known as an anesthetic havingpossible protective effects on the brain against IR injury[26]. The protective effect of thiopental in a reversiblemodel of canine brain stem ischemia was investigated andfound as having some value as a cerebroprotective agent,although the mechanism remains unclear [27]. In anotherstudy, examining the interactive effects of temperature andthiopental and etomidate on extracellular neurotransmitteraccumulation in the rat corpus striatum during cerebralischemia, the administration of those agents during normo-thermia has decreased ischemia-induced dopamine accumu-lation [28]. Although thiopental caused a significantdecrease in the TBARS levels, it has a limited effect on

Fig. 3 Mitochondrial scoresof fetal rat brain in control,sham, IR, vehicle, and propofol,thiopental, etomidate and,midazolam groups. Data wereexpressed as mean±SE. Datawere compared with Kruskal–Wallis ANOVA with post hocMann–Whitney test. Asteriskrepresents comparison relativeto the control, plus signrepresents comparison relativeto the IR injury group, and hashrepresents pairwise comparisonbetween shown groups. *** or+++ or ### for p<0.001; ++

or ## for p<0.01

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the mitochondrial scores. This finding supports that thiopen-tal has neuroprotective effect by preventing lipid peroxida-tion but it did not have enough a preventive effect on themitochondrial damage.

Etomidate, a short-acting anesthetic drug, has been usedin an IR injury rabbit model in a study investigating itsneuroprotective effect [29]. In that study, etomidate wasfound to have a potent neuroprotective effect against IR-induced spinal cord injuries. Authors proposed that thatresult might be related to the ability of etomidate to enhancethe activities of endogenous antioxidants and maintain theion balance in IR-affected tissues. Etomidate was found tohave an adverse effect on mitochondrial function early in thecourse of focal cerebral ischemia, in part, by inhibition ofNOS [30]. Drummond et al. [31] compared the cerebralprotective properties of etomidate, isoflurane, and thiopentalin rat brains. They suggested that thiopental had a protectiveeffect but etomidate and isoflurane increased the volume ofinjured brain. Guo et al. [32] evaluated etomidate as aneuroprotective agent in the brain stems in dog brains. Theysuggested that etomidate provided a limited protection dur-ing brainstem ischemia. We found that etomidate decreasedthe TBARS levels but it did not cause a significant decreasein the mitochondrial score. This finding supports that eto-midate has a neuroprotective effect by preventing lipidperoxidation but it did not have enough preventive effecton the mitochondrial damage.

Midazolam is a short-acting drug in the benzodiazepineclass. An anesthetic dose of midazolam in a rat model hasreduced neuronal damage and improved neurologic outcome7 days after focal cerebral ischemia, however, midazolam alsocaused transient hemolysis [33]. Ravlo et al. [34] comparedthe effect of midazolam and thiopental on the general condi-tion of the neonate following cesarean section anesthesia withthese induction agents. They suggested that midazolamwas assafe as thiopental for induction and maintenance of anesthesiafor elective cesarean section. We found that midazolam hasneuroprotective effect by preventing lipid peroxidation andmitochondrial damage. This finding is well correlated with thestudies showing neuroprotective effect of midazolam [33, 35].Because of its neuroprotective effect and safety, midazolammay be used for emergency cesarean section in cases ofintrapartum asphyxia.

Kelicen et al. [36] concluded that propofol and thiopentalcould protect against the actions of reactive oxygen speciesby impairing endothelium-dependent relaxation in rat aortaand suggested that those drugs had free radical scavengeractivities. Hence, we also think that lipid peroxidation pre-venting effect of propofol and midazolam in accordancewith the results of their study may have free radical scaven-ger activity on neural structures in intrauterine IR injury.Thus, these drugs can protect the brain long before neuronalor mitochondrial damage.

In summary, there are several studies related to the effectof anesthetic drugs on the central nervous system duringsurgical procedures in general and in emergency cesareandelivery in particular. There is always a need to protectneuronal integrity of the central nervous system of hypoxicfetuses. In conclusion, according to our TBARS values andEM findings obtained with ultrastructural evaluation andmitochondrial scoring of fetal rat brain samples in an intra-uterine IR model, the anesthetic drugs including propofol,thiopental, etomidate, and midazolam decreases the lipidperoxidation back to control values while only propofoland midazolam have a protective effect on mitochondrialdamage. Further studies might be required in order to inves-tigate neural effects of these drugs on molecular levelsbefore evaluation of these results in clinical settings.

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