| Objective: Perinatal hypoxic-ischemic brain injury is an important cause of neurodevelopmental impairment and disability. It's well-known that the main death'form of neuron after HIBD is apoptosis. It'a protective machinery for brain after HIBD to inhibit the death of neuron by apoptosis. This study is just in a model of neonatal rat hypoxic-ischemic brain damage (HIBD) to analysis quantitatively the expression of caspase-3 and bcl-2 after HIBD by immunohistochemical technology and investigate the effects of bFGF on neurons after HIBD in the pathological process of pro-apoptosis and anti-apoptosis as well as on the expression of caspase-3 and bcl-2 after HIBD and provide the foundation of experiment and theory for clinic applying neurotrophic drugs.Materials and Methods:⑴ preparation of the model: 7-day-old Wistar rats were selected (the brain'development level of which were the best familiar to neonate),nutritive suitably and weighted 10-15g without the distinction of sex and nest. The pups were anesthetized with procaine(2%) andwere allowed to recover 2-3h after the left common carotid artery were exposed and ligated, then placed in a chamber with a humidified gas mixture(8.00±0.5% oxygen in nitrogen) for 2h. The temperature of the mixture gas and the chamber was kept at 370C. Following hypoxic exposure, the pups were returned to their biological dams until sacrificed. Immediately after HIBD, the neurobehaviors of the rats were evaluated and the standards were that the rats turned left and even fall down or their forelegs bend inward while lifted and so on. Those who conformed to the above standards were successful and the others were excluded. ⑵ animal grouping: 120 rats after HIBD were divided randomly into 2 groups: HIBD group and bFGF treating group. HIBD group was divided randomly into 8 subgroups again: namely 1,12,24,48,72,168h and 14d,21d(n=6). bFGF treating group was also divided randomly into 3 groups : treating group immediately after HIBD ,treating group after HIBD'threee days, treating group after HIBD'seven days and each of three treating groups was divided randomly into 4 groups once more: namely 72,168h,14d,21d(n=6). At the same time, the sham-operated group (in which the rat,left common carotid artery was exposed but not ligated and was sacrificed after operation) was established as the control group (n=5) for comparison with HIBD group and bFGF treating group.⑶ Medication: All of bFGF treating group after HIBD were treated with bFGF (8×103U/kg)in enterocelia daily once andall of HIBD group were treated with the same dosage' physiological saline for comparison with bFGF treating group at the same time.⑷Sampling and Fixation: The rats of HIBD group and bFGF treating group were sacrificed at each time point. The brain tissue were fixed with 4% polyformaldelyde for eight hours, then embedded with paraffin,sectioned as usual,stained with HE to observe the morphology with light microscope and stained with immunohistochemistry to detect Caspase-3 and Bcl-2 positive cells of cerebral cortex. The number and area density of positive cells were examined on 10 fields of a light microscope(×400) by the CMIAS pathological picture analysis system. The sample of electron microscope was fixed with 2.5% olutaradehyde and osmic acid, then embedded with resin and ultramicrotomied, observed and took some pictures.Results: 1 Light microscope (HE): At 1 hour after HIBD, some neurons of the left cerebal cortex were seen wrinkled, in which cytoplasm were ocidophily and nuclei were pyknotic. At 12 hours spotty necrosis was seen and diastem expanded. At 24-48 hours the typical local necrosis was seen, in the center of which the brain tissue thoroughly disappeared and around the center of which the neurons were malalignmental, wrinkled and turned into triangular or irregular in which nucleus were pyknotic and overstained where astroglia multiplied, expanded and swelled. At 48-72hours local hemonhage was seen accompanied with lymphocyte, infiltration. Hemonh...
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