| ObjectiveIn our study, we observed the dynamic changes of caspase-3 mRNA in the brain tissue of neonatl rat with HIBD , and explore the mechanism and significance of neuron apoptosis in neonatal rat induced by hypoxia-isxhemia. Fructose-1,6-diphosphate(FDP) was the intermediary metabolite of glucose, it could ameliorate HIBD though enhancing intercellular ATP concentration , stabilizing Ca2+ concentration and repressing the release of free radicals et al. Based on the above study, we also observed the effect of FDP on the expression of caspase-3 gene in the brain tissue of neonatal rats with HIBD, and explored the neuronal protective mechanism of FDP. Methods1. Mading of HIBD model: Neonatal 7-day-old Wistar rats were under a middle anterior neck incision, the left common artery was isolated and ligated, then the pups were exposed to hypoxic enviroment(8%O2) for a hours. We observed rats behavior ability, then observed microscopical changes.2. Expression of caspase-3 mRNA: 7-day-old Wistar rats were randomly divided into groups of sham-operation ,HIBD6h,24h,3d,6d. six pups in each groups, we measured the expression of caspase-3mRNA by RT-PCR.3. The study of the neuronal protective mechanism of FDP: 7-day-old Wistar rats were randomly divided into groups of HIBD control group, saline-treated group, FDP-treated group . Each of FDP-treated group was divided into groups of high, middle and low dose, we measured the expression of caspase-3 gene at 24h after HIBD by RT-PCR.Result1. Observing of behavior ability of rats: Behavior ability of neonatal rats was normal before the experiment, but abnormal changes happened following hypoxia-ischemia : irrited restless and rolled at 5-10min after entering the hypoxic enviroment, subsequent gradually emerged musle vibrating , head shaking , were unable to reverse the body, also emerded the spasm, seriousely died during hypoxia. The behavior of the sham-operation group was normal.2. HE staining and the histological studySham-operation group: There was no obvious sign of neuronal damage and with cells of apparently normal appearance in the brain.HIBD6h group: There was slight edema in the brain tissue and degenerated neurons were scattered with mild shrunken somata, eosinophilic cytoplasm and intensely staining nuclei.HIBD24h/72h group: The edema in the brain tissue was apparent, the morphological alteration of the neuron were cellular shrinkage, cytoplasmic homogeneous eosinophilia, nuclear pyknosis, and the proliferation of glial cell appeared.HIBD6d group: The edema in the brain tissue was decrease , and the proliferation of glial cells was apparent.3. The dynamic changes of caspase-3 mRNA: Caspase-3 mRNA had relative high-level expression in sham operation group, compared with sham operation group, the expression of caspase-3 mRNA increased at 6h after HIBD a peaked at 24h, hereafter graduately decreased, it kept in relative high level at 5d.4. The neuronal protective mechanism of FDP : There was no different sifnificantly in the expression of caspase-3 gene between the saline-treated group and HIBD group(P>0.05), there was also no different significantly between the FDP-treated(low dose) group and above the two groups(P>0.05). The expression of caspase-3 gene in the other FDP-treated groups(high dose and middle dose) downregulated, there was different significantly campared to above the three groups(P<0.05), but there was no different significantly between the two groups(P>0.05).Conclusion1. We confirmed the success of the model HIBD in neonatal rats through observing the animals behavior ability and the histosspathology of brain tissue.2. Hypoxia-ischemia could induce the expression of caspase-3mRNA in the brain tissue of neonatal rats, and its overexpression might play a role in the neuron apoptosis. The relative treatment of caspase-3 would be open a window for HIBD of neonate.3. The neuronal protective mechanism of FDP might be related to downregulate the gene expression of caspase-3 in... |
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