Effects Of Minocycline On The Expression Caspase-12 After The Focal Cerebral Ischemia And Reperfusion Injury In Rats

Objectives: This study approach the Minocycline on the Neuronal apoptosis,the expression of Caspase-12 Protein during the focal cerebral ischemia and reperfusion injury.Methods: This research makes use of the focal cerebral ischemia and reperfusion model induced by middle cerebral artery occlusion (MCAO) through suture method for 60 minutes followed by reperfusion 24 hours in rats. 45 healthy male Wistar rats (230±10)g were randomly divided into Sham group(n=15), ischemia and reperfusion group(I/R)(n=18) and Minocycline group(n=12). To judge the model bases on Zealonga's scoring and TTC staining results. To observe Barin histopathological changes after focal cerebral ischemia and reperfusion, HE staining, TUNEL method were used; and immunohistochemistry, RT-PCR were used to observe Minocycline'influence on the expression of Caspase-12 protein and/or mRNA in the focal cerebral ischemia and reperfusion tissue.Results:1. The rats are normal in Sham group, but development typical symptoms of neurological impairment in I/R group. TTC staining showed the cerebral tissue is red in Sham group, cortex of ipsilateral prefrontal parietal temporal lobe and external corpora striatum is white in I/R group. The model is successfully maked up.2. HE staining showed the morphology of neurons of Sham group was normal. In I/R group,the neurons in ischemia penumbra area(cortex of ipsilateral prefrontal lobe and internal corpora striatum) and hippocampus region were very little in size and amount, array disorderly and loose. There existed a lot of apoptotic neurons,showed karyopyknosis, chromatin concentration, nuclear fragmentation, et al. In Minocycline group, the number of normal neurons in ischemia penumbra and hippocampus CA1 region increased, The normal neurons and apoptotic neurons are staggered.3. Apoptotic cell showed nuclear in the TUNEL assay. There were few positive cells in Sham group,while in I/R group,positive cell increased gradually, appeared in both ischemic central and penumbra area. In Minocycline group, there were less positive cell than ischemia and reperfusion group (p<0.05).4. There was trace expression of Caspase-12 protein in Sham group. The expression of Caspase-12 is apparent in I/R group (p<0.05) . Their spatial distributions were coincidence with the result of TUENL assay. The expression of Caspase-12 became apparent in Minocycline group than that in sham group, but compared with ischemia and reperfusion group, the expression of Caspase-12 in Minocycline group became significantly weaker (P<0.05).5. In sham group, the expression of Caspase-12 mRNA is low. The expression became significantly high in I/R group (p<0.05) . The expression of Caspase-12 in Minocycline group is lower than that in ischemia and reperfusion group, but higher than sham group(P<0.05).Conclusions:1. Neuronal apoptosis plays important role during cerebral ischemia and reperfusion injury, and apoptotic neuron increased gradually in ischemic penumbra area and hippocampus region. Minocycline could attenuate pathological change after cerebral ischemia reperfusion, show a neuroprotective effect.2. Minocycline obviously inhibited transient focal cerebral ischemia induced apoptosis in ischemic penumbra area and hippocampus CA1 region, relieve neuronal injury.3. Minocycline can decrease neuronal apoptosis, inhibit the expression Caspase-12 protein and mRNA in the cerebral ischemia and reperfusions, so as to protect the brain.