Ultrashortwave irradiation for the repair of sciatic nerve injury and its mechanism

Abstract

Objective To observe the effect of low doses of ultrashortwave therapy (USW) on sciatic nerve injury and to deduce its possible mechanism.Methods Fifty-four Sprague-Dawley rats were randomly divided into a USW group,a control group and a normal group with 18 rats in each.Each group was then sub-divided into 1 week,2 week and 3 week subgroups with 6 rats in each.A model of peripheral nerve injury was established by forceps clipping of the sciatic nerve in the USW and control groups.The USW group was then treated with USW exposure.Rats from the appropriate subgroups were sacrificed after 1,2 and 3 weeks of treatment.Sciatic nerve samples were stained using hematoxylin-eosin and toluidin blue.Expression of basic fibroblast growth factor (bFGF) was detected by immunohistochemical methods.Results Degeneration of axons was observed in both the therapy and control groups after 1 week,and regeneration at the end of the 2nd and 3rd weeks.The number of axons with myelin sheaths was significantly higher in the therapy group than in the control group at the end of the 2nd and 3rd weeks.The expression of bFGF was significantly higher in the USW group compared with the control group at all observation time points.Conclusion USW can obviously accelerate the regeneration of the sciatic nerve,probably through increased expression of bFGF. Key words: Rats; Basic fibroblast growth factor; Sciatic nerve; Ultrashortwave therapy