Protective Effects Of Different Doses Of Recombinant Human Granulocyte Colony-stimulating Factor On Cerebral Ischemia/reperfusion Injury In Rats

Objective: To explore the neural protective effects of rh G-CSF and to reveal its dose-effect relationship by observing the expression of Caveolin-1, COX-2 and change of inflammation in SD rats with cerebral ischemia-reperfusion injury that treated with different dose of recombinant human granulocyte colony-stimulating factor(rh G-CSF).Methods: A total of Sixty male Sprague-Dawley rats were randomly divided into the sham-operated group, the model group,the low-dose the mid-dose and the high-dose treatment group, The cerebral ischemia/reperfusion model was established by Longa suture method. In the different dose of rh G-CSF treatment groups,rats were injected with 25ug/kg,50ug/kg and 100ug/kg respectively subcutaneous1 y at 2h and 24 h after the reperfusion, The sham-operated group and the model group were received the same volume of saline.The neurological function was scored with Longa and Berderson point scale 24 h after reperfusion.The infarction volume were measured by TTC scan 48 h after the reperfusion. The expressions of Caveolin-1 and COX-2 were detected by immunohistochemistry. The brain morphology were observed by HE stain.By calculating the number of inflammatory cells in High-power microsope to reflect brain tissue inflammation.Results: 1.Neurological score showed that compared with sham group,the model group had significant neurological deficit(P<0.01);Compared with model group,the neurological scores decreased significantly in the mid-dose and the high-dose of rh G-CSF treatment group(P<0.01). but no statistical significance was found in low-dose group(P>0.05); the defference between the mid-dose and the high-dose group had no statistical significance in the neurological deficits(P>0.05). 2.TTC scans showed that compared with sham group,the model group had significant Infarction volume(P<0.01);Compared with model group,the infarction volume reduced significantly in the mid-dose and the high-dose of rh G-CSF treatment group(P<0.01). but no statistical significance was found in low-dose group(P>0.05); the defference between the mid-dose and the high-dose group had no statistical significance in the infarction volume(P>0.05). 3.Inflammatory cell of brain tissue showed that compared with sham group,the inflammatory cell in model group increased greatly(P<0.01);Compared with model group,the inflammatory cell decreased significantly in the mid-dose and the high-dose of rh G-CSF treatment group(P<0.01). but no statistical significance was found in low-dose group(P>0.05); the defference between the mid-dose and the high-dose group had no statistical significance in the infarction volume(P>0.05). 4.Immunohistochemical results showed that compared with sham group, the expression of Caveolin-1 and COX-2 protein in model group increased greatly(P<0.01); Compared with model group,the expression of Caveolin-1 increased clearly and the COX-2 decreased significantly in the mid-dose and the high-dose of rh G-CSF treatment group(P<0.01). but the expression of Caveolin-1 and COX-2 in the low-dose group showed no statistical significance(P>0.05). the defference between the mid-dose and the high-dose group had no statistical significance in the expression of Caveolin-1 and COX-2(P>0.05).Conclusions: 1.rh G-CSF could improve the neurological impairment symptoms and promote the recovery of neurological function after cerebral ischemia reperfusion injury in rats. 2.rh G-CSF could provide a neuroprotective role after the cerebral ischemia/ reperfusion injury in rats by increasing Caveolin-1,and then reducing COX-2 expression, thereby inhibiting the inflammatory response. 3.The neuroprotective effect of rh G-CSF on cerebral ischemia reperfusion injury in rats has a dose effect relationship.50ug/kg may be the optimal dose of application.