Objective: To investigate the preventive effect of TGF-beta1 neutralizing antibody on collagen production and adhesion formation of flexor tendon.
Methods: Tendon fibroblasts, epitenon tenocytes, and endotenon tenocytes were obtained from 6 New Zealand rabbit flexor tendons. Each cell culture was supplemented with 1 ng/mL of TGF-beta along with increasing dose of TGF-beta1 neutralizing antibody. Col I production was measured by enzyme-linked immunoabsorbent assay after 3 days. Eighty-four adult New Zealand White rabbits forepaws underwent sharp transection of middle digit flexor digitorum profundus and immediate repair. Then the rabbits were divided into three groups: the normal saline (NS group, n = 36), 1.0 microg/mL TGF-beta1 neutralizing antibody (1.0 microg/mL TGF-beta1 group, n = 36) and 2.0 microg/mL TGF-beta1 neutralizing antibody (2.0 microg/mL TGF-beta1 group, n = 12) were injected in tendon sheath respectively. Tendons were harvested at 4 and 8 weeks for biomechanics testing, histological evaluation and scanning electron microscope observation. Tendons were harvested at 1, 2, 4 and 8 weeks to determine the mRNA expression of TGF-beta1 and Col I by in situ hybridization.
Results: ELISA exhibed that TGF-beta1 enhanced Col I production and the neutralizing antibody significantly inhibited TGF-beta1-induced Col I production in all 3 cell cultures with a dose-dependent. At 4 and 8 weeks after operation the gliding excursion of the tendon and the simulated active flexion in NS group were less than that of 1.0 microg/mL TGF-beta1 group and 2.0 microg/mL TGF-beta1 group. There was significant difference between NS group and 1.0 microg/mL TGF-beta1 group, 2.0 microg/mL TGF-beta1 group (P < 0.05). The tendon anastomosis breaking strength showed no significant differences among three groups (P > 0.05). Scanning electron microscope and histological observation showed that collagen fibers arranged irregularly in NS group, but arranged regularly in 1.0 microg/mL TGF-beta1 group and 2.0 microg/mL TGF-beta1 group at 4 and 8 weeks after operation. The in situ hybridization results revealed that TGF-beta1 and Col I mRNA expression in 1.0 microg/mL TGF-beta1 group was lower than that in NS group at each time. There was significant difference between two groups (P < 0.05).
Conclusion: TGF-beta1 neutralizing antibody can inhibit the function of the TGF-beta1 effectively and prevent adhesion formation after the flexor tendon injured and repaired.