Neuroprotective effect of magnesium sulfate treatment on fetal brain in experimental intrauterine ischemia reperfusion injury

Objective.?The aim of this study was to demonstrate the neuroprotective effect of magnesium sulfate on ischemia–reperfusion-induced injury in fetal rat brain.

Methods.?Twenty-four, 19-days pregnant rats were randomly allocated into four groups. Fetal brain ischemia was induced by clamping the utero-ovarian artery bilaterally for 20 min and reperfusion was achieved by removing the clamps for 30?min. The control group consisted of noninjured rats. No treatment was given in the ischemia–reperfusion group; whereas 1?ml saline and 600?mg/kg magnesium sulfate was administered in the vehicle and the treatment groups 30?min before ischemia reperfusion injury. Lipid peroxidation in the brain tissue was determined as the concentration of thiobarbituric acid-reactive substances (TBARS) for each fetal rat. A one-way analysis of variance and post hoc test were used for statistical analysis.

Results.?TBARS levels were found to be increased after ischemia reperfusion injury when compared with controls. Magnesium sulfate treatment prevented the increase in TBARS after ischemia reperfusion injury.

Conclusions.?We have shown that magnesium sulfate decreases TBARS levels significantly in fetal rat brain subjected to ischemia reperfusion injury and may have potential therapeutic benefits by reducing oxidative stress after intrauterine ischemia–reperfusion-induced fetal brain damage.     

Metformin reduces ovarian ischemia reperfusion injury in rats by improving oxidative/nitrosative stress

ObjectiveTo assess the preventive role of metformin on rat ovarian ischemia reperfusion injury.Materials and methodsForty rats were divided equally into five groups; Group 1: sham, Group 2: surgical control with 3-hr torsion and detorsion, Group 3: 50 mg/kg p.o. metformin 30 min before 3-hr torsion, Group 4; metformin just after detorsion, Group 5; metformin 30 min before torsion and just after detorsion. Bilateral ovaries and blood sample were obtained seven days after detorsion for biochemical and histopathological evaluation.ResultsOvarian tissue total anti-oxidant status (TAS) levels were significantly increased in group 4 when compared to group 1, 2 and 3 (all p < 0.01). In addition, there was a significant decrease in tissue oxidative stress index (OSI) level in group 4 with respect to group 2 (p < 0.01). Moreover, serum levels of OSI were significantly higher in group 2 with respect to group 1 and 5 (both p < 0.05). Similarly, there was significant increase in serum levels of peroxynitrite in group 2 as compared to serum levels in group 3 and 5 (p < 0.01 and 0.05, respectively). Furthermore, there were significant decrease in histopathological scores metformin and sham groups when compared to rats in the control group (Group 2).ConclusionMetformin reduces ischemia reperfusion injury in rat torsion detorsion model by improving histopathological and biochemical findings including TAS, OSI and peroxynitrite.     

An investigation about the inhibition of acute ischemia/reperfusion damage by dexmedetomidine in rat ovarian tissue

Reperfusion has always been “the emergency intervention” to ischemic tissue. For a given period of time, tissue injury due to ischemia and reperfusion is more serious than injury due to ischemia only. Groups were as: Group 1: 25 µg/kg dexmedetomidine + ischemia/reperfusion group. Group 2: 10 mg/kg yohimbine +25 µg/kg dexmedetomidine + ischemia/reperfusion group. Group 3: Ischemia/reperfusion (control) group. Group 4: Healthy rats. Rat ovaries were exposed to a 3-hour ischemia and then reperfusion ensured for 2 hours. After ischemia/reperfusion, total glutathione, malondialdehyde, 8-hydroxyguanine levels and histopathological investigation were studied. The highest total glutathione and the lowest malondialdehyde and DNA damage levels were determined in dexmedetomidine group when compared to control group. The difference between yohimbine + dexmedetomidine and the control group was insignificant. Dexmedetomidine protects the ovarian tissue of the rat from I/R injury. It is hypothesized that this protective effect of dexmedetomidine is mediated by the α-2 adrenergic receptors. Dexmedetomidine could be useful for attenuation of tissue damage after I/R and prevention of I/R-related complications.     

Protective effects of erythropoietin on ischemia/reperfusion injury of rat ovary

Objectives

To evaluate the effects of erythropoietin (EPO) as an antioxidant and tissue protective agent and study the biochemical and histopathological changes in experimental ischemia and ischemia/reperfusion (I/R) injury in rat ovaries.

Study design

36 Adult female rats were used. The experimental groups were designed as Group 1: sham operation; Group 2: bilateral ovarian ischemia; and Group 3: 3 h period of ischemia followed by 3 h reperfusion. Group 4 rats were administered a 5000 IU dose of EPO, before 0.5 h of ischemia, and then bilateral ovarian ischemia was applied. After a 3 h period of ischemia, the bilateral ovaries were removed. In Group 5, a 3 h period of bilateral ovarian ischemia was applied. 2.5 h after the induction of ischemia, the rats were administered the same dose of EPO. At the end of a 3 h period of ischemia, 3 h reperfusion was continued after the ovaries were removed. Group 6 underwent a sham operation after administration of 5000 IU/kg of EPO. After the experiments, superoxide dismutase (SOD), inducible nitric oxide synthase (iNOS), and myeloperoxidase (MPO) activity were determined, and histopathological changes were examined in all rat ovarian tissue.

Results

Ischemia and ischemia/reperfusion increased the iNOS and MPO activity while decreasing the SOD activity significantly in comparison to the sham group. The 5000 IU/kg of EPO before ischemia and I/R reversed the trend in iNOS and MPO activities. The levels of SOD were decreased by the ischemia and I/R. The administration of EPO before ischemia and I/R treatments also reversed the trend in the SOD levels. In the ischemia/reperfusion plus EPO groups, though we observed minimal vascular dilation in the ovary stroma and some degenerative cell clusters, most of cellular structures did not show any pathological changes.

Conclusions

Administration of EPO is effective in reversing tissue damage induced by ischemia and/or ischemia/reperfusion in ovaries.     

Protective effect of infliximab on ischemia/reperfusion injury in a rat ovary model: biochemical and histopathologic evaluation

Objective

The aim of this study was to investigate the effect of infliximab on experimentally induced ovarian ischemia/reperfusion injury (IRi).

Study design

A total of 42 female rats were equally divided into 6 experimental groups; group 1: sham operation, group 2: 3-h ischemia, group 3 and 4: 3-h ischemia, 3-h reperfusion, group 5 and 6: 3-h ischemia, 24 h reperfusion. In group 4 and group 6, 30 min before reperfusion, infliximab was administered intraperitoneally at a dose of 5 mg/kg. Bilateral ovaries were removed for histopathologic and biochemical analysis. Serum MDA (sMDA), tissue MDA (tMDA), serum NO (sNO), tissue NO (tNO) and serum catalase concentrations were analyzed. Tissue damage of ovarian tissue was scored by histological examination.

Results

The infliximab administration significantly lowered the sNO, tNO and sMDA concentrations in group 4 compared to group 3 (p = 0.041, p = 0.025 and p = 0.035, respectively). sNO, tNO and sMDA concentrations were also lower in group 6 when compared to group 5, but this differences were not significant (p > 0.05). On the other hand, tMDA concentrations were lower in infliximab-applied groups when compared to ischemia/reperfusion groups (group 3 vs. 4 and 5 vs. 6) (p = 0.045 and p = 0.048, respectively). Moreover, histopathologic tissue damage scores in infliximab administration groups were significantly lower than in ischemia/reperfusion groups (p < 0.001).

Conclusion

Infliximab attenuates I/R-induced ovarian tissue injury in rats subjected to ischemia/reperfusion.     

Vaginal delivery and serum markers of ischemia/reperfusion injury.

OBJECTIVE: Vaginal deliveries have been associated with pelvic organ prolapse and incontinence. The objective was to show whether markers of ischemia/reperfusion injury are dependent upon the mode of delivery and length of labor. METHOD: Complete venipuncture sets were obtained on 62 subjects. All samples collected were analyzed for serum creatine phosphokinase (CPK) and lactate dehydrogenase (LDH). Lipid peroxidation was analyzed, using thiobarbituric acid reactive substances (TBARS), on a subset of 37 patients. RESULTS: There was a significant increase in CPK from admission to 1 h postpartum and postpartum day 1 in vaginal delivery versus cesarean delivery. Longer second stages were associated with significant increases in CPK. There were no significant changes in either LDH or TBARS from admission to any other time point regardless of mode of delivery. CONCLUSION: Vaginal delivery and longer second stages were associated with a much greater increase in one of these injury markers.     

Effect of fetal hypoxia on heart susceptibility to ischemia and reperfusion injury in the adult rat

OBJECTIVE: Epidemiologic studies showed an association between adverse intrauterine environment and ischemic heart disease in the adult. We tested the hypothesis that prenatal hypoxia increased the susceptibility of adult heart to ischemia-reperfusion (I-R) injury. METHODS: Time-dated pregnant rats were divided between normoxic and hypoxic (10.5% oxygen from day 15 to 21) groups. Hearts of 6-month-old male progeny were studied using Langendorff preparation and were subjected to two protocols of I-R: 10 minutes of ischemia and 3 hours of reperfusion (I-R(10)) or 25 minutes of ischemia and 3 hours of reperfusion (I-R(25)). RESULTS: Prenatal hypoxia did not change basal left ventricular (LV) function. I-R(10) produced myocardial stunning and a transient decrease in LV function in control hearts but caused myocardial infarction and a persistent decrease in postischemic recovery of LV function in hypoxic hearts. I-R(25) caused myocardial infarction in both control and hypoxic hearts, which was significantly higher in hypoxic hearts. The postischemic recovery of LV function was significantly reduced in hypoxic hearts. I-R(25)-induced activation of caspase-3 and apoptosis in the left ventricle were significantly higher in hypoxic than control hearts. There was a significant decrease in LV heat shock protein 70 and endothelial nitric oxide synthase levels in hypoxic hearts. Prenatal hypoxia did not change beta(1)-adrenoreceptor levels but significantly increased beta(2)-adrenoreceptor in the left ventricle. In addition, it increased G(s)alpha but decreased G(i)alpha.CONCLUSIONS: Prenatal chronic hypoxia increases the susceptibility of adult heart to I-R injury. Several possible mechanisms may be involved, including an increase in beta(2)-adrenoreceptor and the G(s)alpha/G(i)alpha ratio, and a decrease in heat shock protein 70 and endothelial nitric oxide synthase in the left ventricle.     

缩宫素对大鼠产后出血肾脏缺血再灌注损伤病理改变和抗氧化机制的影响

目的探讨缩宫素对妊娠大鼠产后出血致肾脏缺血再灌注损伤的保护作用及其可能的机制。 方法将妊娠足月Wistar大鼠随机(随机数字表法)分为3组,每组30只。即缺血再灌注组、缩宫素处理组和对照组。建立大鼠产后失血性休克再灌注模型,观察肾脏的病理组织学改变并检测血中肌酐(Cr)、血尿素氮(blood urea nitrogen,BUN)的水平和肾组织中丙二醛(MDA)、过氧化物歧化酶(SOD)及谷胱甘肽－过氧化物酶(GSH-PX)3种抗氧化损伤指标的活性。各组间指标的比较采用SNK法分析。 结果(1)缺血再灌注组肾脏间质灶状出血,肾小球萎缩,肾小管肿胀;缩宫素处理组肾脏间质出血明显减轻,肾小球及肾小管结构基本正常。(2)缺血再灌注组Cr(151.58±14.31)μmol/L,BUN(48.73±2.48)mmol/L;缩宫素处理组Cr(83.43±4.67)μmol/L,BUN(37.57±0.50)mmol/L;两组比较差异有统计学意义(q＝3.1551,3.1526;P<0.05)。(3)缺血再灌注组,肾组织中MDA(0.88±0.13)nmol/mg,SOD(28.54±1.31)U/mg,GSH-PX(2.94±0.24)U/mg;而缩宫素处理组MDA(0.12±0.56)nmol/mg,SOD(52.23±2.29) U/mg,GSH-PX(5.83±0.14)U/mg,两组比较差异有统计学意义(q＝3.8293,3.1232,2.9756;P<0.05)。 结论缩宫素对产后失血性休克大鼠再灌注后的肾脏病理改变和肾功能具有一定的保护作用,其机制可能与抑制脂质过氧化反应有关。     

Effects of mode of delivery on pro-oxidant/antioxidant balance in fetal circulation

Objective: This study was undertaken to assess the influence of mode of delivery on the balance between pro-oxidant/antioxidant systems in fetal circulation.

Materials and methods: Both umbilical arterial and venous blood samples were obtained from 37 pregnant women who delivered by spontaneous vaginal delivery (VD group) and from 29 pregnant women who delivered by elective cesarean section (CS group). Oxidative stress and antioxidant activity were evaluated by reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP), respectively.

Results: The d-ROMs values of the VD group were higher than that of the CS group in both umbilical arterial and venous blood and these differences were found to be statistically significant (p?p?p?p?Conclusions: Our statistical analyses suggest that vaginal delivery has an effect on increasing oxidative stress as a result of the stress of labor and that an elective cesarean section does not impair the mother’s oxidative stress status. Furthermore, the high BAP values in all the measurements suggest that neonates just after birth have the ability to cope with oxidative stress.

• Rationale

• In many studies, the diversity of views on the influence of mode of delivery on the redox status of neonates is likely to be caused by the use of different biomarkers to measure either the oxidative stress, the antioxidant activity, or both. Furthermore, incomplete explanation for sampling cord blood in these studies, either arterial, venous blood or both, complicates matters. To solve the above, this study was designed to assess the effects of mode of delivery on both pro-oxidants, via d-ROMs, and antioxidants, via BAP, in both umbilical arterial and venous blood samples obtained just after birth. There are no existing studies of BAP in both umbilical arterial and venous blood to which we can refer. In conclusion, our study suggests that the pro-oxidant/antioxidant balance in neonates just after birth is better than may be expected when compared to the potentials of adults (including pregnant mothers) according to interpretations of BAP/d-ROMs. This can be understood that neonates may have already been endowed with the ability to cope with oxidative stress, as informed by high BAP values in both umbilical arterial and venous blood. Vaginal delivery may have an effect on increasing oxidative stress as a result of the stress of labors (as measured by d-ROMs), and an elective cesarean section, which has better BAP/d-ROMs in umbilical venous blood than that of vaginal delivery, may not impair the mother’s oxidative stress status.

     

Blockade of endothelin receptors with bosentan limits ischaemia/reperfusion-induced injury in rat ovaries

Objective

To investigate the role of endothelin receptors in ovarian ischaemia/reperfusion (I/R) injury in rats using the endothelin receptor antagonist bosentan.

Study design

Group 1: sham operation; Group 2: sham operation and bosentan 60 mg/kg; Group 3: bilateral ovarian ischaemia; Group 4: 3-h period of ischaemia followed by 3 h of reperfusion; Groups 5 and 6: bosentan 30 and 60 mg/kg, respectively, with bilateral ovarian ischaemia applied 30 min later; the bilateral ovaries were removed after 3 h of ischaemia; Groups 7 and 8: 3 h of bilateral ovarian ischaemia was applied, with bosentan 30 and 60 mg/kg, respectively, administered 2.5 h after the induction of ischaemia; following the 3-h period of ischaemia, 3 h of reperfusion was applied, after which the ovaries were removed.

Results

Ischaemia and I/R decreased superoxide dismutase (SOD) activity and the level of glutathione (GSH) in ovarian tissue, but increased the level of malondialdehyde (MDA) significantly compared with the sham operation group. Bosentan 30 and 60 mg/kg before ischaemia and I/R decreased the MDA level and increased SOD activity and the GSH level in the experimental groups. The serum levels of the inflammatory cytokines interleukin (IL)-1β, IL-6 and tumour necrosis factor-α were also measured in the I/R injury model in rat ovaries. The levels of these cytokines were significantly higher in the ischaemia and I/R groups compared with the sham operation and sham operation plus bosentan groups. The histopathological findings also demonstrated the protective role of bosentan against I/R-induced injury in rat ovaries.

Conclusion

Administration of bosentan protects the ovaries against oxidative damage and I/R-induced injury.     

Development of a guinea pig model of chorioamnionitis and fetal brain injury

OBJECTIVE: The purpose of this study was to develop a guinea pig model of chorioamnionitis to study the mechanisms that lead to fetal brain injury.Study design Pregnant guinea pigs at 70% gestation were inoculated intracervically with 1000 to 2500 colony-forming units of Escherichia coli. Guinea pigs were killed 2 to 3 days after bacterial inoculation. Maternal blood and fetal amniotic fluid samples were analyzed for proinflammatory cytokine tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 levels with the use of enzyme-linked immunosorbent assay kits. Fetal brains were stained for evidence of cell death with NeuroTacs stain. RESULTS: Of 34 maternal guinea pigs that were given an intracervical inoculation of E coli, 8 guinea pigs showed microbiologic evidence of chorioamnionitis in the amniotic fluid. Tumor necrosis factor-alpha and interleukin-6 were significantly higher (P<.05) in amniotic fluid samples that were obtained from sows that were subjected to intracervical inoculation with bacteria as compared with control animals (n=6 control maternal animals). These results were observed even if no bacteria were found subsequently on culture of the amniotic fluid from inoculated animals, which indicated that indirect exposure to infectious agents was sufficient to cause an elevated inflammatory response in the fetus. Levels of white matter injury were greater in fetuses that were exposed to bacterial infection in utero, as compared with control animals (P<.05). This result was found in the staining of periventricular and cortical white matter for the immunolabeling of activated caspase 3 and NeuroTacs staining for cells that exhibited evidence of apoptotic cell death (positive stain with evidence of karyorrhexis). CONCLUSION: Intracervical inoculation with E coli results in chorioamnionitis in guinea pigs that is associated with fetal brain injury.     

Effects of caffeine on neuronal apoptosis in neonatal hypoxic-ischemic brain injury

Abstract

Objective: Hypoxia-ischemia (HI) in rat pups leads to strong activation of apoptosis, and apoptosis contributes significantly to cerebral damage in the perinatal period. Caffeine displays a broad array of actions on the brain. The aim of this study was to investigate the effects of caffeine on neuronal apoptosis in a hypoxic-ischemic neonatal model.

Methods: Twenty-four seven-day-old Wistar rat pups were subjected to right common carotid artery ligation and hypoxia for 2?h. Sham group (n?=?8) had a median neck incision, but the rats were not subjected to ligation or hypoxia. The pups were treated with 20?mg/kg/day caffeine citrate (n?=?8) or saline (n?=?8) immediately before HI and at 0, 24, 48 and 72?h post-hypoxia. Neuronal apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) and caspase-3 in the hippocampus and parietal cortex of both hemispheres.

Results: The numbers of apoptotic cells in the hippocampus and parietal cortex were significantly higher in the saline group than they were in the sham group (p?<?0.0001). The number of apoptotic cells in the hippocampus (p?<?0.0001) and parietal cortex (p?<?0.0001, TUNEL and p?=?0.001, caspase-3) were higher in the caffeine-treated group than they were in the sham group, but the number of apoptotic cells decreased significantly in the caffeine-treated group compared with the saline group in the hippocampus (p?<?0.0001, TUNEL and p?=?0.001, caspase-3) and parietal cortex (p?=?0.001, TUNEL and p?=?0.002, caspase-3).

Conclusions: We show that caffeine administration in hypoxic-ischemic brain injury reduces neuronal apoptosis in the developing brain. We suggest that caffeine may be effective in reducing brain injury.     

Effects of ciprofloxacin and quercetin on fetal brain development: a biochemical and histopathological study

Purpose: Teratogens cause birth defects and malformations while human development is being completed. In pregnancy, urinary tract infection (UTI) is a common health problem caused by bacteria. The fluoroquinolones such as ciprofloxacin, levofloxacin, moxifloxacin, and gemifloxacin can treat various types of bacterial infections successfully. The aim of this study is to determine whether the use of ciprofloxacin during pregnancy causes oxidative stress on brain tissues of the fetus, and whether quercetin contributes to prevent this damage if stress has already occurred.

Materials and methods: In our study, 22 young female Wistar albino rats weighing 250?g were used. Rats were mated overnight in separate plastic cages. Female rats were regarded as pregnant when a vaginal plug was observed, and these were divided into four groups of control, ciprofloxacin, quercetin, and cipro?+?quercetin. Two daily i.p. 20?mg/kg doses of ciprofloxacin were administered to ciprofloxacin group between 7 and 17 d of pregnancy. Throughout the study, daily (20 d) 20?mg/kg quercetin was dissolved in corn oil and administered to the quercetin group by oral gavage. Rats were fed ad libitum throughout the study. Fetuses were taken by C-section on the 20th day of pregnancy. Thereafter, the brain tissues were subjected to histological assessments and biochemical analyzes.

Results: The experimental groups were compared with the control group; ciprofloxacin affected fetal development, especially caused damage to neurons in brain tissue and cause hemorrhagic defects. And also, it was determined that many parameters were affected such as antioxidant parameters, enzyme levels and levels of malondialdehyde (MDA) (a marker of lipid peroxidation). Quercetin is a member of flavonoid with strong antioxidant properties, and our results indicate that the use of ciprofloxacin in pregnancy can result damage to fetal brain tissue.

Conclusions: Unlike these results when some parameters are evaluated it is understood that this harmful effects suppressed by quercetin.