Effects of transplantation of microencapsulated rabbit sciatic nerve on expressions of GDNF after spinal cord injury in rats

Objective To explore the effects of transplantation of microencapsulated rabbit sciatic nerve cells on glial cell line-derived neurotrophic factor(GDNF) expressions after spinal cord injury(SCI) in rats.Methods Eighty Sprague Dawley rats were randomly divided into four groups: microcapsule group(n=25),cell group(n=25),injury control group(n=25) and normal group(n=5).The rabbit sciatic nerve cells suspension was prepared from rabbits.SCI was conducted by hemisection injury of spinal cord.Different groups were respectively implanted with 10 μl microencapsulated cells suspension(microcapsule group),10 μl sciatic nerve cells suspension(cell group) and 10 μl physiological saline(injury control group).Spinal cord tissues were taken out(five rats per hour) 2 days,7 days,14 days,21 days and 28 days after operation respectively,while corresponding tissues were collected(one rat per hour) in normal group.All tissues were embedded in paraffin and sectioned.Meanwhile,immunohistochemical stain was applied for the detection of GDNF.Results The GDNF positive staining was mainly seen in the cytoplasm of neurons and gliocytes.The expressions of GDNF were increased two days after SCI and were reached the highest leve1 21 days after SCI.The expression levels of GDNF in microcapsulated group were remarkably different from those in injury control group and cell group(P0.05).Conclusion It suggests that the transplantation of microencapsulated rabbit sciatic nerve cells could suppress inflammatory reaction and improve the expressions of GDNF,thus accordingly promote the recovery of motor function in rats.