大鼠骨骼肌挫伤愈合过程中caspase-3的表达及时间规律

目的观察大鼠骨骼肌挫伤愈合过程中,caspase-3的表达及其变化规律。方法制作大鼠右小腿骨骼肌挫伤模型,应用免疫组织化学法、Western blot法及caspase-3活性测定法对不同时间段大鼠骨骼肌挫伤后caspase-3表达进行检测。结果免疫组织化学及Western blot均显示,挫伤周边区caspase-3的活性随时间延长逐渐升高,5d时达最高峰,随后活性逐渐下降。免疫组织化学染色结果显示,伤后3～5d挫伤处坏死的骨骼肌细胞被清除干净,新形成的肌细胞大量增生,且新形成的肌细胞胞浆内有caspase-3表达;损伤后7～14d,新形成的肌细胞内仍然有caspase-3的阳性表达。结论大鼠骨骼肌挫伤后,挫伤周边骨骼肌表达caspase-3有一定的时间规律性,可望作为推断骨骼肌挫伤时间的指标之一;大鼠骨骼肌挫伤后,新形成的肌细胞表达caspase-3,提示caspase-3可能在骨骼肌分化过程中起重要作用。

Time-dependent expression of caspase-3 during contused skeletal muscle wound healing in rats

Objective: To investigate the expression of caspase-3 during contused skeletal muscle wound healing in rats and to explore the applicability of caspase-3 in wound age estimation. METHODS: Male Sprague-Dawley rats undergone anesthesia with 2% pentobarbital sodium (45 mg/kg) were struck by a single strike at the skeletal muscle of the right leg, then were sacrificed by cervical dislocation at different post-traumatic intervals. The changes of caspase-3 activity were assessed by imunohistochemistry, Western blot and caspase-3 colorimetric assay. The skeletal muscle of non-contusion rat's were used as controls. RESULTS: No caspase-3 was detected in skeletal muscle in the control group. The expression level of caspase-3 in the peripheral area of contused rat skeletal muscle increased gradually and maximized on the fifth day after injury, and then decreased gradually. Caspase-3 was also detected in the regenerated skeletal muscle within 7-14 days after injury. CONCLUSION: The expression of capase-3 in the peripheral area of contused rat skeletal muscle indicated that it may play a pivotal role in apoptosis of the wounded skeletal muscle and may be used as a marker for wound age estimation. The expression of capase-3 in regenerating skeletal muscle suggests that caspase-3 activity may be used for skeletal muscle differentiation.