The Relationship Between TGF-β1 And Inflammatory Cytokines Of Bone-tendon Junction With Repetitive Jumping Training

Objectives: The purpose of this study was to discuss the effect of TGF-β1 on some cytokines in patellar-patellar tendon junction of rabbits during different periods of repetitive jumping training and to reveal the mechanism of changes in those cytokines by observing the time sequence regularity of TGF-β1 and the cytokines under the rabbit quantitative repetitive jumping model.Methods: 32 female white rabbits of New Zealand were randomly divided into 2 groups(taking one unilateral hind leg of each rabbit as a sample,N=64)which were respectively controlling group(CON,n=32)and Jumping group(JUM,n=32).Each of these 2 groups was divided as 4 smaller groups for 2 weeks,4 weeks,6 weeks and 8 weeks according to the intervention time.The grouping condition was represented as “The mean of intervention+ Intervention time”.For example,The controlling group lasting for 4 weeks was represented as CON4 W.Results: Immunohistochemistry showed that the expression of TGF-β1(P<0.01),TNF-α(P< 0.05),IL-1β(P< 0.01)and COX-2(P< 0.01)had significantly increased while the expression of MMP-1(P< 0.01)had decreased compared with the CON group at the same time point;The expressions of TGF-β1(P<0.01),IL-1β(P<0.01),COX-2(P<0.01),COL-I(P<0.01)and the ratio of COL-I/COL-III(P< 0.01)in JUM6 W group had significantly increased while the expression of MMP-1(P< 0.01)in JUM6 W group had decreased;The expressions of TGF-β1(P< 0.01)and IL-1β(P< 0.05)in JUM8 W group had significantly increased.Conclusions: 1)An approximately similar inflammatory process had taken place under the stimulation of repetitive jumping training.This process gradually faded away during period 4W to 6W of jumping training and then vanished till 8W of jumping training which indicated that this process is not a typical inflammatory process.The jumping training caused the increase of inflammatory cytokines but no degradation of COL-I.2)The effect of repetitive jumping training on anabolism was accomplished by increasing TGF-β1 and inhibiting the synthesis of MMP-1 and was finally reflected in the up regulation of COL-I and the increase of COL-I/COL-III.3)During the first 4w to 6w of repetitive jumping training,TGF-β1 promoted the release of inflammatory cytokines TNF-α、 IL-1βand COX-2 while inhibited the expression of mmp-1.During the 6w to 8w of repetitive jumping training,TGF-β1 inhibited the release of inflammatory cytokines TNF-α and COX-2 and played an antergic role against the pro-inflammatory signals of IL-1β.