转化生长因子β1中和抗体对转化生长因子β诱导肌腱胶原和术后粘连的影响

背景:研究表明,转化生长因子β1在肌腱损伤愈合过程中增加了肌腱细胞胶原的合成和术后粘连的形成.目的:观察转化生长因子β1抗体对转化生长因子β诱导的肌腱细胞胶原产生及术后粘连形成的影响.设计、时间及地点:随机分组观察实验,于2005-09/2006-06在同济医学院实验动物中心完成.材料:选择2-5月龄新西兰大白兔,体质量3.5～4.5 kg.转化生长因子由美国SantaCruz B iotechnology公司提供.方法:取兔屈指肌腱分离肌腱成纤维细胞、腱外膜细胞和腱内膜细胞,将细胞随机分成2组,实验组加入1 μg/L转化生长因子β后,再加入0.1,0.5,1.0mg/L转化生长因子β1中和抗体,对照组不添加任何试剂,酶联免疫吸附实验测定Ⅰ型胶原.取84只兔行中趾屈指肌腱切断吻合术,将其中36只兔随机分成3组,腱鞘内分别注入生理盐水、1.0,2.0 mg/L转化生长因子β1中和抗体,4,8周后取出肌腱行肌腱粘连检测、生物力学测定、组织学观察和扫描电镜观察;余48只兔随机分成2组,腱鞘内分别注入生理盐水和1.0mg/L转化生长因子β1中和抗体,1,2,4,8周后取出肌腱,原位杂交方法测定肌腱转化生长因子β1和Ⅰ型胶原mRNA的表达.主要观察指标:各组兔肌腱细胞胶原产生及术后粘连情况.结果:酶联免疫吸附实验显示,转化生长因子β1能明显提高肌腱细胞Ⅰ型胶原的产生;转化生长因子β1抗体能降低3种细胞Ⅰ型胶原的产生,随抗体质量浓度增加,Ⅰ型胶原水平逐渐降低,且呈剂量依赖性;术后4,8周,与1.0,2.0mg/L转化生长因子β1组比较,生理盐水组屈趾肌腱滑动距离较短,模拟主动屈曲度明显受限(P<0.05),最大抗断裂载荷各组间比较差异无显著性意义(P>0.05).扫描电镜和组织学观察结果显示,术后4,8周生理盐水组胶原纤维排列紊乱,1.0,2.0 mg/L转化生长因子β1组胶原纤维排列整齐.原位杂交结果显示,术后各时间点1.0 mg/L转化生长因子β1组转化生长因子β1和Ⅰ型胶原mRNA表达均低于生理盐水组(P<0.05).结论:转化生长因子β1抗体能有效抑制转化生长因子β1在肌腱损伤修复中的作用,减少粘连形成.

Effects of transforming growth factor beta 1 neutralizing antibody on collagen production and adhesion formation of the flexor tendon

BACKGROUND: Studies have showed that transforming growth factor-β1 (TGF-β1) could yield to the collagen synthesis and adhesion formation of tendon cells at the process of healing. OBJECTIVE: To investigate the preventive effect of TGF-β1 neutralizing antibody on the collagen production and adhesion formation of flexor tendon. DESIGN, TIME AND SETTING: Randomized grouping observational experiments were performed in the Experimental Animal Center of Tongji Medical College between September 2005 and June 2006. MATERIALS: New Zealand white rabbits aged 2-5 months, weighing 3.5-4.5 kg. TGF was offered by Santa Cruz Biotechnology, USA. METHODS: Sheath fibroblasts, epitenon tenocytes, and endotenon tenocytes were obtained from rabbit flexor tendons. Cells were divided into two groups at random. In the experiment group, each cell culture was supplemented with 1 μg/L of TGF-β at increasing dose (0.1, 0.5, 1.0 mg/L) of TGF-β1 neutralizing antibody. No reagents were given in the control group. Collagen Ⅰ production was measured by enzyme-linked immunoabsorbent assay. Eighty-four adult New Zealand white rabbit forepaws underwent sharp transection of middle toe flexor digitorum profundus, followed by immediate repair. Thirty-six adult New Zealand white rabbit were divided into three groups randomly (n=12), injecting with the saline, 1.0 mg/L TGF-β1 neutralizing antibody and 2.0 mg/L TGF-β1 neutralizing antibody into tendon sheath respectively. Tendons were harvested at 4 and 8 weeks to conduct adhesion detection, biomechanical testing, histological evaluation and scanning electron microscopy observation. The remaining 48 New Zealand white rabbits were divided into two groups randomly (n=24), undergoing the saline and 1,0 mg/L TGF-β1 neutralizing antibody injection in tendon sheath respectively. Tendons were harvested at an increasing time interval (1, 2, 4, 8 weeks) and analyzed by in situ hybridization to determine the mRNA expression of TGF-β1 and collagen Ⅰ. MAIN OUTCOME MEASURES: Collagen production and adhesion of rabbit tendon cells. RESULTS: ELISA exhibited that TGF-β1 increased collagen Ⅰ production and the addition of neutralizing antibody significantly reduced TGF-β-induced collagen Ⅰ production in all cell cultures. The effect between antibody and collagen Ⅰ was dose dependent. At 4 and 8 weeks after operation, the gliding excursion ratio of the tendon was shortened and the simulated active flexion ratio were less in saline group compared with 1.0 and 2.0 mg/L TGF-β1 groups (P < 0.05). The tendon anastomosis breaking strength was shown no significant differences among 3 groups (P > 0.05). Scanning electron microscopy and histological observation showed that collagen fibers arranged irregularly in saline group, but arranged regularly in 1.0 and 2.0 mg/L TGF-β1 groups at 4 and 8 weeks after operation. The in situ hybridization examination revealed that TGF-β1 and collagen Ⅰ mRNA expression in 1.0 mg/L TGF-β1 group was lower than that in saline group at each time (P < 0.05). CONCLUSION: TGF-β1 neutralizing antibody can inhibit the function of the TGF-β1 effectively following the flexor tendon injury and repair, and can prevent adhesion formation.