Study Of The Expression And Role Of BFBF,TGF-β1 In Lumbar Ligamentum Flavum Hypertrophy

Study Design:To detect the exprssion of basic fibroblast growth factor(bFGF) and transforming growth factor betal(TGF-β1) mRNA in lumbar ligamentum flavum,and clarify the role of them in the process of hypertrophy of the ligamentum flavum.Background:Hypertrophy of the ligamentum flavum is one of the most important pathophysiological changes of lumbar stenosis,but the hypertrophy mechanism remains unclear.According to the previous studies,it may be the accumulation of scar tissue in the ligament due to the fibrosis.Although substantial progress of the role of bFBF and TGF-β1 in the pathomechanism of skin scar has been attained,there is not report about their role in the hypertrophy of ligamentum flavum.Due to the similar fibrosis process of hypertrophied ligamentum flavum and skin scar,we thought that bFBF and TGF-β1 may play a same role.Method:Forty-eight ligamentum flavum samples were obtained for the study, twenty samples from the patients with lumbar disc herniation(LDH),twenty hypertrophied ones from those with lumbar stenosis and eight thin control ligaments. They were divided into three groups to measure their thickness using magnetic resonance imaging and detect the expression of bFBF and TGF-β1 mRNA using Real-Time and Quantitative reverse transcription poly chain reaction(RT-PCR) respectively.Rerults:The ligamentum flavum thickness was 4.86±0.51mm in hypertrophy group, 2.44±0.29mm in LDH group and 2.26±0.14mm in control one respectively.Comparing with the two laters,the thickness in hypertrophy group was much larger(p＜0.001,p＜0.001),but there was not statistical difference between LDH group and control one(P＞0.05).The expression of bFGF mRNA was higher both in hypertrophy and LDH groups than control one(p＜0.01,p＜0.01),the average level was moderately high in the LDH group,but no statistical difference was observed between the prvious two groups(P＞005).However,the expression of TGF-β1 mRNA was not similar as the bFGF.In LDH group,it was higher than hypertrophy group and control one(P＜0.05,P＜0.01),and the expression level was lower in contol group than hypertrophy one. Conclusions:With the increasing of ligamentum flavum thickness,the expression of bFGF mRNA increase persistently,but the TGF-β1 mRNA had a obvious drop in the late stage.It may be concluded that TGF-β1 played a main role in the early stage, however,it may have a synergetic effect combined the bFGF which resulted to the persistent fibrosis of the ligamentum flavum,as well in the skin studies.