A Study On The Distribution And Expression Changes Of FSTL1 After Peripheral Nerve Injury

Objective: The present study was designed to observe the expression of FSTL1 in the sciatic nerve trunk,dorsal root ganglion(DRG)and spinal cord ventral horn of the normal adult rats and study the expression changes in different time points after peripheral nerve injury.Which is intended to preliminary investigate the relationship between FSTL1 and Peripheral nerve regeneration.Methods: Thirty healthy SD rats,at the three months old and weighing200-300 g,were divided into five groups: control group(n=6)and four experiment groups(2days,7days,14 days,28days,n=6).We prepared the sciatic nerve transection and end-to-end neurorrhaphy on experiment groups and control groups done nothing.The sciatic nerve trunk,DRG and spinal cord ventral horn of adult rats were cut into paraffin sections in due course.HE staining methods were used to observe the pathological changes of the transected neural stumps.On the other hand,immunofluorescence and double immunofluorescence technique were used to observe the distribution of FSTL1.What’s more,Image pro-plus 6.0 was used to quantitative analysis the typical pictures and got the FSTL1 Integral Optical Density(IOD)for statistics analysis.Results:(1)HE staining results show that Wallace degeneration is occurred in the distal transected neural stumps,which are serious than the proximal.(2)FSTL1 was normal expression in the myelin and nervebasal lamina tube in the sciatic nerve trunk.The Integral Optical Density of FSTL1,tested by software at different time-points,indicated that the FSTL1 protein was expressed and up-regulated at 2 days in never transected distal stumps.Down-regulation of FSTL1 protein level was at7,14 and 28 days.The data of 2,14 and 28 days were significantly difference(p<0.05).(3)ATF3was located in neuronal nuclei of injury DRG cell.In rat DRGs,co-localization studies show that FSTL1 was expressed in cytoplast and extracellular matrix of small neurons at high levels and in large neurons at low levels.Up-regulated of FSTL1 protein level was at 2 days and down-regulation of FSTL1 protein level was at7,14 and 28 days.The data of2,7,14 and 28 days were significantly difference(p<0.05).(4)Co-localization studies show that FSTL1 was located in the neuronal somas,process and synaptic space of motor neurons.Up-regulated of FSTL1 protein level was at 2 days and downregulation of FSTL1 protein level was at 7,14 and 28 days.The data of2,7,14 and 28 days were significantly difference(p<0.05).Conclusions: Our research showed that FSTL1 widely express distribution in the sciatic nerve trunk,DRG and spinal cord ventral horn of the adult rats.The expression level of FSTL1 offered upgrade firstly than descending latter tendency after injury which indicated that it may play an important role in the biological process of peripheral nerve regeneration.