The impact of erythropoietin on inflammation and neuronal apoptosis after sciatic nerve injury in rats

Abstract

Objective To explore the effect of erythropoietin on inflammation, neuronal apoptosis and the possible mechanism after sciatic nerve injury in rats and provide experimental basis for clinical treatment of peripheral nerve injury.Methods Left sciatic nerve defect was created in 36 female Sprngue-Dawley rats which were divided into three groups:normal saline(NS)group,erythropoietin(EPO)group and nerve growth factor(NGF)group.NS,EPO and NGF were administered by intraperitoneal injection in the NS group,EPO group and NGF group,respectively.At 7 and 14 days after the operation,the morphological change of L5 dorsal root ganglion neurons was observed by light microscope.The expression of IL-6 and TNF-α mRNA of both proximal and distal stumps were quantified using RT-PCR.The neuronal apoptosis of L5 dorsal root ganglion was assessed by TUNEL.Results At 7 and 14 days after the operation,the expression of IL-6 mRNA of both proximal and distal stumps in EPO group was less than that in the NS group(P ＜ 0.01).The expression of IL-6 mRNA of distal stumps in EPO group was less than that in the NGF group(P ＜ 0.01).The expression of TNF-α mRNA of both proximal and distal stumps in EPO group was less than that in the NS and NGF groups(P ＜0.01)7 days postoperatively.The expression of TNF-α mRNA of distal stumps in EPO group was less than that in the NS group(P ＜0.05)14 days postoperatively.At 7 and 14 days after the operation,neuronal apoptosis in EPO treatment group was lower than NS treatment group(P ＜ 0.01),while neuronal apoptosis in EPO treatment group was lower than NGF treatment group(P ＜ 0.05)14 days postoperatively.Conclusion EPO can attenuate injury-induced inflammation and inhibit dorsal root ganglion apoptosis,which may provide protective effect for sciatic nerve injury in rats. Key words: Sciatic nerve; Apoptosis; Inflammation; Erythropoietin; Injuries