The Impairment And Protection Of Cerebral Tissue Following Experimental Intracerebral Hemorrhage

Objective The pathologic impairment and the mechanism of protection of cerebral tissue following experimental intracerebral hemorrhage (ICH) were studied in the research to definitude the histological and cellular lesion after ICH, thus the theoretical basis of the treatment of ICH in the clinic might be obtained by the results of this study. Material and Methods The rat model of experimental ICH was made by the method of injection of arterial blood into the caudate nucleus, and a more injection of hirudin was adopted to make the model of hirudin-intervention group. The slides of cerebral tissue were stained by HE, methylthioninium chloride, LFB and PTAH. The pathologic changes after ICH were observed with optic and electron microscope. The cellular skeleton lesion following ICH was studied with immunohistochemical (IHC) stains of MAP-2 and GFAP. The cellular apoptosis phenomena was observed with the methods of flow cytometry, DNA electrophoresis, TUNEL and IHC stains of bcl-2, bax, caspase-3 and TNF-α. The relative expressing content of caspase-3 mRNA in the neurocytes around the hematoma was detected by method of RT-PCR. Results The activity of the rats following experimental ICH decreased. The hemiplegia and circle motion could be observed among the ICH rats. The round hematoma in the area of caudate nucleus was existed by the gross observation. The pathological changes of ICH rat included tissue softening around the hematoma, edema, swelling and necrosis of neuron and astrocyte. Nissl body around the nucleus decreased. Rupture or turbulence of never fiber, demyelination and the lesion of cellular skeleton could be observed. By the electron microscope, swelling of neurocyte, cavitation, membrane of neurocyte and nucleus lesion, cavitation and cristae disruption of mitochondrion, rarefaction of neuropil and karyopyknosis could be observed. After the formation of hematoma, the number of positive cells of bcl-2 IHC stain gradually decreased and arrived at the valley at the time of 1d, while that of bax, caspase-3, TNF-α and TUNEL gradually increased and arrived at the peak at the time of 1d-2d,2d-3d,3d and 3d-5d respectively. The content of caspase-3 mRNA gradually increased and arrived at the peak at the time point of 2d. The Ap (Apoptosis) subpeak could be observed in each group with the method of flow cytometry. The percents of cellular number in the Ap subpeak gradually increased and got the peak at the time point of 5d. The ladder like stripe formed by rupture of DNA might be observed in the group of the time points of 2d-7d with the method of DNA electrophoresis. In the hirudin-intervention groups, cellular necrosis, cerebral edema and lesion of cellular skeleton alleviated, the number of positive cells of caspase-3 IHC stain and TUNEL decreased significantly. Conclusion The rat model of experimental ICH could be made by the method of injection of arterial blood into the caudate nucleus. The lesion of cellular skeleton of neuron and astrocyte and the phenomena of apoptosis could be observed around the hematoma. The cellular apoptosis might be induced by the increasing expression of caspase-3, the increasing content of bcl-2 and decreasing content of bax and the ratio of bcl-2/bax could cause apoptosis, it might also be caused by the increasing of intracellular TNF-α. Hirudin injected in the hematoma could significantly alleviate tissue necrosis, edema, the lesion of cellular skeleton and the apoptosis of neural cells.