| The mechanism of brain damage post cerebral ischemia is very complicated. It includes not only neuron's acute swelling and necrosis but also cell apopto-sis. Cell apoptosis has close relationship to the brain damage post cerebral ischemia and plays important roles in infarction formation. Many studies show that gene caspase-1 family are very important to cell apoptosis and have central effect.Using immunocytochemical method and TUNEL dye, we studied the cell apoptosis and caspase-1 expression in both infarction center and ischemic penumbra of mice's brain following acute focal cerebral ischemia-reperfusion. We found that caspase-1 expression enhance in focal cerebral ischemia-reperfusion and it promote neuron apoptosis, which suggest that caspase-1 inhibitor can lighten brain ischemic damage and it will provide a new therapy method for brain ischemia.Materials and methodsMale Wistar mice,weight 230-340,randomly divided,was used for brain ischemia-reperfusion model prepare. After 2 hours' occlusion the cerebral middle artery was reperfused. The animals of control and experiment group were killed after 3,24,48,72 hours' survive ( n = 5 ). Sham operation and normal control group were also prepared ( n = 5 ). Open the thorax when mice were deeply anesthetized, perfuse 0.9% natrii chloridi sonly via left ventricle. Remove the brain rapidly and keep it in thcliquid nitrogen. All samples were cut coronary at opticchiam and 4mm behind it and made into paraffine samples. 1. immunocytochem-istry:The paraffine sections (4um) cut continuously from sample center were prepared for HE dye,caspase-l immuocytochemical dye and TUNEL dye. 2. Statistics deal;Record the positive cells in infarction center and ischemic penumbra. The results were statistics with ANOVA. The difference is significant when P <0.05.Results1.The character of caspase-1 positive cell's distribution: Only scattered positive cells are found in sham operation group, control group and contra-hemi-sphere of experimental group. In infarction center, positive cells are mainly found in 3h group. In ischemic penumbra,a few positive cells appear in 3h group. In 24h group, the positive cells increase at pick and maintain till 48h,but decrease after 72h.2. The character of TUNEL positive cell's distribution; Only few positive cells are occasionally found in sham operation group and control group. There is no positive cells are found in contra-hemisphere of experimental group. In infarction center, positive cells are mainly found in 3h group and decreased obviously in 24h group. In ischemic penumbra, only a few positive cells appear in 3h group. In 24h group,the positive cells increase obviously and maintain till 48h, but decrease after 72h.3. No matter in infarction center or in ischemic penumbra, the distribution of caspase-1 and TUNEL positive cells are identical.DiscussionRecent studies have confirmed that the neuron death following ischemic brain damage includes necrosis and cell apoptosis. Studies show that serious and long-time ischemia will lead to neuron necrosis and light and short-time ischemia is easy to cause neuron apoptosis. Neuron apoptosis plays important roles in delayed neuron death. Studied have shown that caspase-1 is closely related to neu-ron appotosis after brain ischemia.Our study showed that when the brain was reperfued after 2 hours' ischemia , caspase-1 expression and apoptosis cells in ischemic center and penumbra change continually with the time after reperfusion and the distributions of them are identical. In ischemic penumbra , caspase-1 expression and apoptosis cells reach pick at 24-48h after reperfusion. In ischemic center,caspase-1 expression and apoptosis cells reach pick at 3h after reperfusion and decrease afterwards. In ischemic center, neurons necrosis increase and neurons alive decrease with the time post ischemia-reperfusion extend, so caspase-1 expression decrease. In ischemic penumbra,caspase-1 expression enhances with the time extend and promotes neuron apoptosis.Concerning the m...
|
PDF Full Text Request