Experimental Studies Of Effects Of Decorin In Flexor Tendon Healing

Objective: After tendon injury, adhesion formation will greatly decreased hand functions. Transforming growth factorβ(TGF-β) is a key cytokine to adhesion formation and fibrillogenesis of collagen fibrils. As one TGF-βneutralizing proteoglycans(PGs), decorin can not only block the effects of TGF-βbut also manipulate fibrillogenesis. The purpose of this study in vivo and in vitro was to investigate the possible role and mechanisms of decorin during the process of tendon healing and provide theory bases for further clinical results.Methods: Firstly, Tendon cells derived from the tissue of rabbits flexor tendon were harvested and cultured in vitro with decorin of serial concentration(0.25,1.25,2.5,5μg/ml). After 12,24 and 48 hours of culture,the cell proliferation rates were measured by MTT colorimetric determation. After 24 hours of culture with decorin of 2.5μg/ml concentration, we investigated the morphology of tendon cells and analyzed the cell cycle distributions with flow cytometer.After synchronization,cell culture medium were supplemented with 2.5μg/ml of decorin. After 12 hours, collagen type I was measured and compared with unsupplemented control cultures by immunocytochemical staining and immuneoflurorescence assay;the mRNA leve of collagen type I was detected by semi-quantitative reverse transcription polymerase chain reaction(RT-PCR).Secondly, eighteen Japanese flapeared rabbits were randomized into 2,4,8-week groups with 6 ones in each group.(1)Second toes were obtained from rabbits'hind limbs to expose deep flexor tendon which was cross-cut. Right tendon of second toes used as experimental toes were directly injected with 100μl decorin (0.25g/L) at the sutured site, and left tendon of second toes as control toes were injected with 100μl phosphate buffer solution(PBS). Plaster was used for fixation and immobilization. (2)Adhesion observation: Adherent tissues tendon sheaths and tendon were exposed to observe the adherent shape of tendon at 2,4 and 8 weeks after operation. There are four grades of tendon adhesion from no adhesion to massive adhesion. (3)Histological observation: Six sections were obtained respectively from the sutured region of experimental toes and control toes at 2,4 and 8...