Experimental study of NGF and BDNF Gene expression in acute peripheral nerve injury

Abstract

Objective To investigate changes in gene expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) after acute peripheral nerve injury in rats.Methods Forty-eight SD rats were randomly divided into 8 groups.Right sciatic nerve injury model was established by transection and direct repair in rats of 7 groups.Another group of unoperated rats served as normal control.One cm of sciatic nerve segment centered at the repair site was harvested at postoperative day 1,2,3,4,5,6 and 7 respectively.Total RNA was extracted and expression of NGF mRNA and BDNF mRNA was quantified using reverse transcriptase-polymerase chain reaction (RT-PCR).Results NGF mRNA and BDNF mRNA could be detected in normal rat sciatic nerves at a relatively low level.Obvious increase of NGF mRNA expression was seen first day after sciatic nerve injury,which maintained at a higher level there after.BDNF mRNA rose to a higher than normal level 4 days after nerve injury.At postoperative day 5 and day 6 it dropped to nomal.At postoperative day 7 BDNF mRNA increased again.Conclusion Changes of NGF and BDNF expression are not synchronized after rat sciatic nerve injury.This indicated that different factors are involved in regulating NGF and BDNF mRNA content in acute peripheral nerve injury. Key words: Peripheral nerves; NGF; BDNF; mRNA