Does Functional Recovery Of Sciatic Nerve Injuried Rats Can Be Facilitated By Edaravone In Early Stage?

Objective: This study was designed to assess the role of edaravone on neural regeneration and neurological recovery, meanwhile discuss the neural protection mechanism of edaravone in rat model of sciatic nerve injury, so as to provide experimental evidence for clinical treatment of the peripheral nerve injury.Methods:Forty-eight healthy SD rats were randomly divided into four groups equally and given oblique skin incision on the right hip after anesthesia. The muscles were separated bluntly, and then the sciatic nerve were exposed. For rats of group A, the sciatic nerve on the right side was only slightly raised. But for rats of group B, C or D, the right-side sciatic nerve were clamped by one obtuse hemostatic forceps to create a 3-mm length of crush injury, and labelled with microscopic sutures around the epineurium in the traumatic zone. Then the wounds were sutured by layers. The validance of the traumatic model was assesed with complete palsy of the right foot and toes, and areflexia of the claw-spreading awake from anesthesia. Rats of group B were injected with 1ml of normal saline o.d. intraperitoneally, to days-14 after surgery. Rats of group C were injected with edaravone(3mg/kg) o.d. intraperitoneally, diluted with normal saline to 1ml, to days-14 after surgery. And rats of group D were injected with dexamethasone(1mg/kg) o.d. intraperitoneally, diluted with normal saline to 1ml, to days-3 after surgery. Then general observation, functional index of sciatic nerve, MDA content and SOD activity, and expression of Bcl-2 and Bax by immunohistochemistry were measured at the desired time point. Based on the above indicators, the role of edaravone on neural regeneration and functional recovery in rat model of sciatic nerve injury was assessed. All data were shown as x±s, using ANOVA for the statistics by software of SPSS16.O.Results: During the first week, the sciatic functional index of rats in each group had no significant difference(P>0.05). During the second week, the sciatic functional index of rats received edaravone treatment was better than that only suffered from clamp injury(P<0.05), showing the effect of edaravone on the functional recovery of sciatic nerve injury. However, no statistical difference of sciatic nerve index was found between the rats received edaravone and that received dexamethasone(P>0.05). But the variance of MDA/SOD content and the counts of Bcl-2/Bax positive cells in rats received dexamethasone were better than both rats received edaravone treatment and only clamp injury(P<0.05), although there had indeed significant difference between the edaravone-treatment group and the injury-control group(P<0.05).Conclusions:1.It is feasible to assess the sciatic nerve injury using the rat model of crush injury.2. Edaravone can improve the sciatic nerve function of rats two weeks after surgery.3. Edaravone can significantly improve the SOD activity and reduce the MDA content in sciatic nerve injury model, alleviating the free radical damage to cells and inhibiting the lipid peroxidation.4. When sciatic nerve were injured, edaravone can inhibit the development of apoptosis in anterior horn cells of corresponding spinal cord segments by both enhancing the expression of anti-apoptosis gene Bcl-2 in the L4-L6 spinal anterior horn cells, and reducing the expression of pro-apoptotic gene Bax in the spinal anterior horn cells.In summary, this study showed that edaravone had good effect on neural repairment and regeneration. So it is worthy to advocate the use of edaravone clinically for cases having peripheral nerve injury.