The Effects Of G-CSF On The Expression Of Cytochrome C And Caspase-3 Protein Following Focal Cerebral Ischemia/Reperfusion Injury In Rats

Objective To explore the anti-apoptotic mechanisms of G-CSF in brain damage following cerebral ischemia/reperfusion in rats,and provide a new theoretical basis for clinical application.Methods Thirty-six male Sprague-Dawley rats were randomly divided into the sham-operated group,the middle cerebral artery occlusion/ reperfusion group (MCAO/R) and the G-CSF-treatment group, and 12 rats were included in each group. The middle cerebral artery occlusion reperfusion model was established by the suture method.The G-CSF-treatment group received a single dose of 50μg/kg of rhG-CSF which were hypodermicly injected at the onset of reperfusion and 24 hours after the reperfusion. The sham-operated group and MCAO/R group received the same volume of saline. After 48 hours of reperfusion, rats were decapitated in all the groups. The expression of cytochrome C (Cyt C) and Caspase-3 were detected by immunohistochemical method and the apoptosis cells were tested by TUNEL method. The infarction volume was measured by TTC stain and the neurological function scores were assessed on Longa 5-point scale.Results1. The MCAO/R group and G-CSF-treatment group had different degrees of limb paralysis after cerebral ischemia reperfusion.Compared with the MCAO/R group,the neurological scores of the G-CSF-treatment group reduced obviously and the mental state improved,the two groups showed significant difference (p<0.01).2. After TTC staining,the infarction was not found in the sham-operated group,while the left parietal cortex and striatum of cerebral infarction were seen clearly in the MCAO/R group and G-C S F-treatment group.But with the MCAO/R group,the volume of infarction significantly reduced in the G-C S F-treatment group(p<0.01).3. Compared with the sham-operated group,the expression of Caspase-3 and cytochrome C and TUNEL positive cells were significantly increased in the MCAO/R group and G-C S F-treatment group (P<0.01). Compared with the MCAO/R group.the expression of Caspase-3 and cytochrome C and TUNEL positive cells were significantly diminished in the G-CSF-treatment group (P<0.01). Conclusion1. G-CSF can decrease neurological function scores and contribute to the recovery of limbs after the MCAO/R.2. The effects of G-CSF can reduce infarction volume after MCAO/R.3. G-CSF can inhibit the expression of Caspase-3 and cytochrome C positive cells and reduce TUNEL positive cells,which might be the mechanism of G-CSF neuroprotection.