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OBJECTIVE: To investigate the anti-apoptotic effect of ginsenoside Rg1 in neonatal rats with hypoxia ischemia brain damage (HIBD), and to explore the possible signaling pathway involved in anti-apoptosis.
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Objective To investigate the protective effect of melatonin and its possible mechanism for repairing in the immature white matter damage due to brain hypoxia-ischemia (HI).Methods Forty-eight three-day SD rats after birth were randomly divided into 3 groups:sham-operated(SHAM) group,HI group and melatonin treatment(MT) group.Periventricular white matter damage (PWMD) to animal models were estabished according to Rice modeling.MT group was treated with melatonin pre-operatively,immediately postoperation,1 hour postoperation and 24 hours postoperation via intraperitoneal injection,and the other groups were injected with the same volume of dissolvent.The rats were executed by decollation after 2 days and 14 days.The histological changes in periventricular white matter were observed by HE staining and immunohistochemistry.Results For the 3 groups,the structure in ope-ration side of the white matter in the peripheral ventricles of the brain 2 days postoperation were significant different (P ＜0.05).The O4 positive cells decreased one by one/greatest in the SHAM group[(75.548 ± 7.333)/hpf] followed by MT group [(59.971 ± 3.635)/hpf],and HI group [(40.511 ± 2.848)/hpf] (P ＜ 0.05).The expression of Casepase-3 increased in the SHAM group (107.724 ± 10.266),MT group (132.289 ± 8.537),and HI group (202.168 ± 14.367),and the difference was statically significant (P ＜ 0.05).Ventricular index was greater in operation side of the white matter in the peripheral ventricles of the 14-day-brain in the SHAM group(0.928 ±0.063),MT group (1.813 ± 0.110),HI group (2.752 ± 0.201),increasingly,while absorbance value of myelin basic protein decreased one by one in sequence(39.504 ± 1.673,21.729 ± 1.614,11.344 ± 1.118).Conclusions MT plays a role in protecting the periventricular white matter via inhibiting the apoptosis of oligodendrocyte progenitor cell,and thus benefits the PWMD.
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Objective To investigate the possible function of integrin-linked kinase (ILK)/protein kinase B (PKB/Akt) signaling in repair of neonatal rat hypoxia-ischemia brain damage (HIBD). Methods Postnatal day 10 SD rats were randomly divided into hypoxia ischemia (HI) group and sham control group. Rat brains were collected at 0 h, 4 h, 6 h, 12 h, 24 h, 48 h and 72 h after hypoxia ischemia damage. Immunolfuorescence staining was used to observe the distribution and expression of ILK. Western blot was used to detect the expression of ILK, Akt, phosphorylated Akt (p-Akt) and vascular endothelial growth factor (VEGF). Lentiviral vectors expressing ILK shRNA were constructed to inhibit the expression of ILK in neonatal rats. After intracerebroventricular injections of LV-ILK shRNA lentivirus and LV-control respectively, HIBD model was established. Rat brains were collected at 4 h and 24 h after HIBD. Western blot was used to detect the expression of ILK, p-Akt, and VEGF. TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining was used to detect cell apoptosis. Results Immunolfuorescence staining showed that ILK was widely distributed in cortex and hippocampus both in HI group and sham control group. ILK located at cell membrane and cytoplasm. Western blot results demonstrated that ILK protein increased after HI, with a peak at 24 h, and maintained higher level than those in sham control group. The p-Akt protein signiifcantly increased at 4 h after HI, and signiifcantly decreased in the following 24 h, and then increased again, with a peak at 48 h, but the level of p-Akt protein was higher than that of sham control group. The VEGF protein increased at 4 h after HI, with a peak at 12 h, higher than that of sham control group. The expression of Akt protein showed no signiifcant difference between HI group and sham control group. Lentiviral vectors containing RNAi targeting ILK was applied successfully in vivo. At 4 h and 24 h after HIBD model, the expression of ILK, p-Akt, and VEGF proteins in right side brain received LV-ILK shRNA signiifcantly decreased compared with those of right side brain received LV-control at the same time point. And cell apoptosis signiifcantly increased in LV-ILK shRNA group. Conclusions The expression of ILK, p-Akt, VEGF proteins increased after HI. By inhibiting the expression of ILK, the expression of p-Akt and VEGF proteins can be reduced, and cell apoptosis could increase in newborn rats after HIBD. The results suggest that ILK may induce the expression of VEGF through activating the PI3K/Akt signaling pathway, and promote cell survival and angiogenesis after HIBD.
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Objective To observe the expression of hypoxia-inducible factor 1 α (HIF-1α) in rat brain after hypoxia-ischemia(HI),and to explore the possible mechanism of L-thyroxine (L-T4) on HIF-1α expression.Methods Sixty-four postnatal 7-day Sprague-Dawley rats were randomly divided into 4 groups:the sham operation group,HI group,menstruum-treated group and L-T4-treated group.HIBD models were generated according to Rice model method.The rats in menstruum-treated group and L-T4-treated group were respectively administrated of intraperitoneal injection of menstruum with the equal volume and 2 μg/100g L-T4,once a day,for 5 days.The expressions of HIF-1α and phospho-protein kinase B(p-Akt) protein were detected by means of immunohistochemistry.Reverse transcription-polymerase chain reaction was used to detect the level of HIF-1α mRNA.Results The levels of p-Akt protein(50.168 ±4.259),HIF-1α protein (72.795 ±6.121) and HIF-1α mRNA (0.448 ± 0.035) were upregulated compared with those in the sham operation group (8.080 ±0.369,38.581 ± 2.846,0.174 ± 0.015),and the differences were significant (all P ＜ 0.05).The levels of p-Akt protein (82.765 ± 6.271),HIF-1 α protein (117.350 ± 9.374) and HIF-1 α mRNA (0.618 ± 0.042) in L-T4-treated group were higher than those in HI group,and the differences were significant (all P ＜ 0.05).The level of HIF-1 α protein was positively correlated with p-Akt protein in HI group and L-T4-treated group [r(HI) =0.635,P=0.048;r(L-T4) =0.694,P=0.026].Conclusions L-T4 can upregulate HIF-1α mRNA and protein expression in neonatal rats with hypoxia-ischemia brain damage.Phosphatidylinositol-3-kinase/protein kinase B signaling pathway may be involved in L-T4 upregulating HIF-1α mRNA and protein expression.
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Objective To study the role of deferoxamine(DFO)on regulating hypoxia-inducible factor 1α(HIF-1α)expression after hypoxia-ischemia brain damage(HIBD)in neonatal rats,to explore the therapeutic strategy for HIBD. Methods Postnatal day 10 SD rats were divided into four groups: hypoxia-ischemia(HI)group,DFO-treated group,normal saline(NS)-treated group,and sham operation group. HIBD model was established by the ligation of right common carotid artery following the inhalation of nitrogen-oxygen mixtures containing 92% nitrogen and 8% oxygen. DFO-treated group and NS-treated group were treated by intraperitoneal injection of DFO or NS respectively. The brains were collected at 4 h,8 h,and 24 h after hypoxia. HIF-1α protein expression was detected by Western blot analysis,and HIF-1α mRNA expression was detected by using RT-PCR at each time point. Results The synthetic level of HIF-1α protein increased significantly at 4 h,peaked at 8 h,and decreased at 24 h after HI in HI group,as well as NS-treated group. However,in DFO-treated group HIF-1α protein was peaked at 4 h,maintained higher level at 8 h and 24 h after HI. The level of HIF-1α protein was much higher in HI and DFO-treated groups than those in sham controls(P ＜ 0.05). The synthetic level of HIF-1α protein were higher in DFO-treated groups than those in HI groups at each time point(P ＜ 0.05). HIF-1α mRNA expression was higher in DFO-treated groups than those in HI groups at each time point. Conclusions DFO upregulate HIF-1α protein and mRNA expression in neonatal rats with HIBD. The peak of HIF-1α protein expression are also more advanced and lasted longer after DFO-treatment.
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Corticotropin-releasing factor(CRF)is one neuroendocrine peptide which is closely related with the stress.It has been proved that any stress can lead to the person and animal's blood CRF level increasing,and high-level CRF urges the hypothalamic neuron calcium ion inflow.Newborn pediatricians pay more attention to whether blood CRF level can act as one director of assessing severity of newborn hypoxic-schemic brain damage.This article reviews the CRF and it's acceptors,CRF secretion,CRF physiological action and it's adjustment,and hypoxia-ischemia stress and CRF,in order to provide the theory basis for reviewing the severity of hypoxic-schemic brain damage in neonates.
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ObjectiveTo observe the effect of progesterone on progesterone receptor in brain tissue with hypoxia-ischemia brain da-mage(HIBD) in neonatal rats,and discuss the protective mechanism of progesterone on HIBD of neonatal rats.MethodsTwenty-four 7-day-old neonatal rats were randomly divided into 3 groups:sham-operated group,hypoxia-ischemia group and pretreatment group.Rats in hypoxia-ischemia group and pretreatment group were subjected to left common carotid artery ligation,then were exposed to 80 mL/L oxygen and 920 mL/L nitrogen gas in 37 ℃ closed container for up to 2.5 h to establish hypoxia-ischemia encephalopathy(HIE) model.Progestero-ne was injected intraperitoneally into pretreatment group rats respectively at 30 minutes before hypoxia,solution was injected into the first 2 groups.All rats were killed at the 24 hour after operation,immunohistochemistry staining was used to examine the expression of progesterone receptor in brain.ResultsTotally 24 neonatal rats entered the result analysis without loss.Progesterone receptor was expressed in both endochylema and nucleus in every group rat.The amount of the positive cell of progesterone receptor in hypoxia-ischemia group significantly decreased compared with that in sham-operated group(P
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Objective To explore the dynamic changes of hydrogen sulfide(H2S)in the pathological course in cortical tissues at diffe-rent times of hypoxia-ischemia brain damage(HIBD).Methods Fifty-six healthy 7-day-old Sprague-Dawley newborn rats were randomly assigned into 7 groups(n=8):normal group,sham-operated group,HIBD 12 h group,HIBD 24 h group,HIBD 48 h group,HIBD 72 h group,and HIBD 7 d group.HIBD rat models were established by ligating the left common carotid artery,after 2-4 h,followed by exposuring to hypoxia(80 mL/L oxygen and 920 mL/L nitrogen)for 2 h.The achievement of HIBD model was determined by the change on behaviour of neonatal rats.There were no treatment on the normal group,and the left common carotid artery was only separated in the sham group.The left cortical tissues in the experimental group were removed at 12,24,48,72 h,and 7 d after HIBD.H2S amounts in cortical tissues at different times after HIBD were measured by biochemical methods.Results H2S level in cortical tissues in HIBD 12 h group increased significantly compared with sham-operated group(P
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Objective To study changes of aspartate(ASP) and glutamaic acid(GLU) in cerebral cortex of neonatal Sprague-Dawely(SD) rats after hypoxia-ischemia and nitric oxide synthase(NOS) immunoactive expression in cerebral neurons were examined to explore mailuoning′s protective effect on hypoxia-ischemia brain damage(HIBD).Methods The HIBD model was established as follows.The right common carotids of the neonatal SD rats 7 days were temporaily ligatured for 1 hour.Then the neonatal SD rats were exposed to 8% oxygen and 92% nitrogen gas mixture for 2 hours. The ASP and GLU were determined in right cerebral cortex using chromatograph,compared with sham-operated group and mailuoning administrated. Ultrastructure changes of neurons in the right cerebral cortex of neonatal SD rats were observed after sham-operated,hypoxia-ischemia and mailuoning administrated using electronmicroscope.Results The level of excitatory amino acid was promoted in right cerebral cortex after hypoxia-ischemia.The volume of excitatory amino acid was reduced sharply mailuoning administrated. Ultrastructure of neurons in the cerebral cortex showed serious injure after hypoxia-ischemia and ultrastructure of neurons in the cerebral cortex appeared slight damage.Conclusion Mailuoning may possess protective effects to the neurons after hypoxia-ischemia through supplying blood to neurons reducing release of excitatory amino acid.
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Objective To observe the change of neuron-specific enolase (NSE) an d glial fibrillary acidic protein (GFAP) in neonatal rats' cerebral cortex with hypoxic-ischemic brain damage (HIBD). Methods The 7 day- old SD rats were subjected to the ligation of right carotid artery, then were pu t into a hypoxic box to establish a HIBD model. The immunohistochemical method w as used to detect the expression of NSE and GFAP in rats' cerebral cortex. Results ① The NSE decreased in damaged cerebral cortex in HIBD 24 h group, after 7 days it gradually increased but was still lower than that of the controls. ② The expression of GFAP was limited and scarce in control and it did not change in HIBD 24 h group, while in HIBD 7 d group GFAP expression was increased and spread widely in the damaged cerebral cortex. Conclu sion ① The NSE decreases in damaged cerebral cortex in early stage of neonatal rat HIBD, suggesting that NSE is a specific marker for neuron damage . ② The GFAP increases in damaged cerebral cortex in the recovery stage of neon atal rat HIBD, suggesting that GFAP participates the repair of lesion region.