Experimental Study on Fatigue Phenomenon of the Anterior Cruciate Ligament by Excessive Exercise

1.研究了强化训练对双足大鼠前交叉韧带(ACL)生物力学特性和形态特征的影响。在四周的连续6天中，两足大鼠被迫在电动跑步机上以20m/min的速度以20m/min的速度连续跑步30min。在8.3 mm/s和1×10~(-3)mm/s的负荷速率下，运动(E(+)G)大鼠的力量成绩显著低于非运动(E(-)G)大鼠。负荷松弛试验显示E(-)G比E(+)G有更大的负荷松弛现象。E(+)G的前交叉韧带黏度高于E(-)G。E(+)G组成纤维细胞内粗面内质网和溶酶体泡增多，胶原纤维直径在20~120 nm之间。E(+)G组胶原纤维平均直径明显小于E(-)G2组。较小的全层缺损(幼年兔直径*3 mm)可自发修复，而较大的全层缺损不能用软骨修复。在幼兔股骨滑车5 mm全层缺损区，应用bFGF(0.05 ng/h)2周可诱导间充质细胞向软骨细胞分化。8周内，骨痂形态基本恢复正常。另一方面，给予抗碱性成纤维细胞生长因子中和抗体(50 ng/h)两周可抑制3 mm全层缺损区中心的软骨细胞分化。

1.The effect of enforced exercise on biomechanical properties and morphological characteristis of the anterior cruciate ligament(ACL) of bipedal rats was examined. The bipedal rats were forced to run on a motor-driven treadmill at 20 degrees decline and at a speed of 20 m/min for 30 min on each of six consecutive days during the four-week period. Strength results for bipedal rats with exercise (E(+)G) were significantly lower than those for bipedal rats without exercise(E(-)G)at the loading rates 8.3mm/sec and 1*10^3 mm/sec. A load relaxation test showed a larger load-relaxation phenomenon in E(-)G than in E(+)G.The viscosity of the ACL was higher in E(+)G than in E(-)G.In E(+)G,eighty-one percent of the fibroblasts in the ACL were spindle-shaped with indented nucleus. There was an increased number of rough surfaced endoplasmic reticula and lysosomal vesicles in the fibroblasts of E(+)G.The collagen fibril diameters of E(+)G varied in size from 20 to 120 nm. The mean collagen fibril diameter of E(+)G was significantly lower than that of E(-)G.2.The effect of basic Fibroblast Growth Factor(bFGF) on the repair of full-thickness articular cartilage defects was studied. The smaller full-thickness defects(* 3 mm in diameter in adolescent rabbits) are repaired spontaneously, but the larger defects cannot be repaired with cartilage. The administration of bFGF (0.05ng/h) for two weeks elicited the differentiation from mesenchymal cells to chondrocytes in the 5 mm full-thickness defects in the femoral trochlea of adolescent rabbits. Within eight weeks, the defects showed almost complete recovery of epiphyseal morphology. On the other hand, the administration of neutralizing antibody to bFGF (50 ng/h) for two weeks inhibited chondrogenic differentiation in the center of the 3 mm full-thickness defects.