Effects of erythropoietin administrated by intranasal on nerve function and CD31 in cerebral ischemia reperfusion rats

Objective To explore the protective effect of erythropoietin(EPO) administrated by intranasal on cerebral ischemia reperfusion in rats with acute cerebral infarction reperfusion. Methods Total of 100 SD rats were divided into model control group, sham operation group, intraperitoneal administration group (IPEPO group), nasal saline group (INNS group) group, and nasal drug delivery group (INEPO group) with 20 in each group.The middle cerebral artery occlusion model of rat was established by thread embolism method and the NSS method was used to evaluate the neural behavior of rats.The expression of EPO in peripheral blood, cerebrospinal fluid and brain regions of rats were detected by Elisa.The vascular endothelial growth factor(VEGF) in brain was detected by immunofluorescence and then the density of newborn blood vessels in the brain was measured. Results Fifteen days after the operation, the NSS score of INEPO group(3.80±1.61) was significantly lower than that of IPEPO group (11.53±2.11), and the difference was statistically significant(P<0.01). And the levels of EPO in blood, cerebrospinal fluid and different brain regions of rats in INEPO group were higher than that of INNS group(all P<0.01). Compared with IPEPO group, the level of EPO cerebrospinal fluid and different brain regions of rats in INEPO group increased obviously, the difference was statistically significant (all P<0.01), and the EPO concentration of the olfactory bulb was the most obvious(INEPO group: (1 456.90±128.22)pg/ml, IPEPO group: (426.11±36.68)pg/ml, P<0.01). Seventy-two hours after operation, the expression of CD31 in ischemic penumbra of rats of model control group (18.21±3.45), INNS group(18.54±2.58), IPEPO group(27.01±2.13)and INEPO group(35.52±2.79)was increased compared with sham operation group (5.14±1.28), and the difference was statistically significant (all P<0.05). The expression of CD31 in IPEPO group and INEPO group was significantly higher than that in INNS group (P<0.05). In INEPO group, the expression of CD31 increased significantly compared with that of IPEPO group (P<0.05). Conclusion Nasal administration of EPO can effectively improve the neurological function of rats with ischemia-reperfusion, and increase the expression of CD31 in the brain tissue of rats.The effect of nasal administration is better than that of intraperitoneal administration. Key words: Nasal administration; Erythropoietin; Ischemia reperfusion; Cerebral infarction; Angiogenesis; Rat