The Pathogenesis Of Patella-patella Tendon Junction And Patella Tendon Fibrosis Induced By Jumping And Effect Of Cold Water Immersion On Them

Objective: To make rabbits complete jumping exercise of the corresponding time points by electrical stimulation jumping device.And to explore the pathogenesis of PPTJ and PT fibrosis.Meanwhile,to explore the effect of cold water immersion on the fibrosis process of PPTJ after jumping practice.Method: 18-week old New Zealand rabbits were randomly divided into control group(CON)? jumping group(JUM)? cold water immersion after jumping group(JUM+CWI)and cold water immersion group(CWI),and each group divided into 4 time points(2?4?6?8 weeks).JUM was training to jump regularly for 150 times a day,5 days a week.JUM+CWI was taking cold water immersion after jumping exercise for 3 times,5 mins/time.CWI completed the same task of cold water immersion.The PPTJ and PT were harvested in the corresponding time points.The effects of jumping and cold water immersion on histomorphology and the expression of fibrosis and anti-fibrosis related cytokines of PPTJ and PT were described and evaluated by HE ? Safrain O ? Masson ? immunohistochemical staining ?Immunofluorescence staining and Real Time PCR.Result:(1)Compared with the same time point of CON group,FZT?GA?CA?TGF-?1?Smad3?CTGF?COL-I and COL-III of PPTJ were significantly increased in JUM group at all time points(p<0.01);the mRNA and protein of TGF-?1?CTGF?COL-I and COL-III of PT were significantly increased in JUM group at 4-week(p<0.05).Compared with the different time points in JUM group,FZT?GA?CA?TGF-?1?Smad3?CTGF and COL-I of PPTJ were the highest level at 6 weeks(p<0.05);the mRNA and protein of TGF-?1?COL-I and COL-III of PT were the highest level at 4-week(p<0.01).(2)Compared with the same time point of JUM group,FZT?GA?CA?TGF-?1?Smad3?CTGF?TIMP-1?COL-I and COL-III of PPTJ were significantly decreased in JUM+CWI group at 4-week and 6-week(p<0.05);HGF?MMP-1?MMP-9 of PPTJ were significantly increased in JUM+CWI group at 4-week(p<0.01).(3)Compared with CON and CWI groups,the expression of fibrosis related cytokines of PPTJ were significantly increased in JUM+CWI group,the expression of anti-fibrosis related cytokines of PPTJ were significantly decreased in JUM+CWI group.There was no difference between CON and CWI group(p>0.05).Conclusion:(1)PT fibrosis appeared earlier than PPTJ by jumping,PT was in 4-week and PPTJ was 6-week.(2)The mechanism of PT and PPTJ fibrosis was jumping would lead to increase secretion of TGF-?1 and Smad3,up-regulation expression of CTGF,result in increasing synthesis of COL-I,COL-III,leading to collagen area becoming larger,ultimately result in fibrosis pathological changes.(3)The pure cold water immersion had no effect on PPTJ tissue.The cold water immersion after jumping exercise could improve the post-fibrotic PPTJ,and the most obvious role appeared at 4-week.(4)The cold water immersion may inhibit the process of PPTJ fibrosis in two ways.One way was to down-regulate the expression of TGF-?1 and Smad3,and inhibit follow-up signal transduction pathway.The other way was to increase the secretion of HGF,promote TIMP-1 and MMP-1?MMP-9 to restore balance,lower the synthesis of COL-I,COL-III,reduce the collagen area,and inhibit the process of PPTJ fibrosis.