| [Introduction] Subarachnoid hemorrhage, a clinical important disease in neurology, have an serious impact on blood-supply in the central nervous system, induce neurons necrosis and apoptosis widely, affect the function in systems of circulation, respiration, digestorium and endocrine at different levels, and then influence the survival rate and survival quality of patients furtherly. It is a current research focus to reduce the severe secondary injury in academic field. So, this study is about the apoptosis of neurons in subarachnoid hemorrhage.Apoptosis is that, a form of programmed cell death, independent and regulated by genes, in order to remained internal environment stable. There are two apoptosis pathways, one is the activation of cysteine proteases Caspase caused by the death receptors on the membrane, another is activation of cysteine proteases Caspase caused by the apoptosis factors (released by mitochondrion of cytoplasm). The activated Caspases could biodegrade the important cellular proteins and induce apoptosis. Mitochondrion is the control center of cellular biogenic activities, not only the center of respiratory chain and oxidative phosphorylation in cells, but also the regulation and control center of apoptosis. ATP sensitive potassium channels located in mitochondrial membrane, after activation of this channels, potassium ions flow inward to the inner mitochondrial membrane, induced membrane depolarization, then inhibit the flow of calcium ions inward to mitochondrion, to prevent calcium overload. All these functions play a role of neuron-protection.[Objective] This study is to explore the anti-apoptosis effect of ATP sensitive Potassium Channel Openers in central nervous system, with the methods of building subarachnoid hemorrhaged rats model, administrated with diazoxide, evaluating the expression of apoptosis factors (Bc1-2,Bax,Caspase3 ).[Methods] 66 male healthy Wistar rats, weights of 200～250kg, were randomly divided into 3 groups: 6 rats in control group (none of treatment), marked as G1; 30 rats in subarachnoid hemorrhaged group marked as G2; 30 rats in diazoxide group, marked as G3. And the rats of G1,G2 group were randomly divided into 5 subsets, 6 rats in each subset, according to different sacrificed period. The sacrificed period are 6 hours, 1day, 2days, 3days and 7days after model built marked as S1 S2 ...to S5. Experimental animals were injected into its cisterna magna with autogeneic arterial blood to establish Subarachnoid hemorrhaged rat models. Evaluated in neural dysfunction 3 hours later, the qualified rats were put in the research, injected with saline solution in group 1 and diazoxide solution in the group 2. According to scheduled sacrificed periods, rats were decapitated to capture brain and hippocampus isolated on the ice. With the methods of real-time PCR and Western Blot, the mRNA and protein expression of Bcl-2,Bax, Caspase3 in hippocampus were respectively detected. Experimental data was processed with statistical software of SPSS 11.0.[Result] (1) It was significantly that, compared with corresponding subset of subarachnoid hemorrhaged group, in the 1 day and 3 days subset of diazoxide group, the mRNA expressions of Bcl-2 were up-regulated, while in the 2 day and 3 days subset, the mRNA expressions of Caspase3 were down regulated. The differences between control group and these four subsets were significant, but the differences of Bax expressions between diazoxide group and its corresponding subarachnoid hemorrhaged group were not significant. (2) It was significantly that, compared with corresponding subset of subarachnoid hemorrhaged group, in the 3 days subset of diazoxide group, the protein expressions of Bcl-2 were up-regulated, and Caspase3were down regulated. The differences between other corresponding subset ofdiazoxide group and subarachnoid hemorrhaged group were not significant, and thedifferences of Bax expressions were not significant too.[Conclusion] Diazoxide, the ATP -sensitive Potassium Channel Openers, up-regulatedthe expression of Bcl-2(anti-apoptosis) and down regulated the expression ofCaspase3 (inducing apoptosis), play a key role of protecting neurons in subarachnoidhemorrhaged rats model. |
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