大鼠股薄肌原位游离移植模型的建立及相关肌萎缩指标的检测

Establishing an Experimental Animal Model of Free Muscle Transfer with Rat Gracilis Muscles

目的建立大鼠股薄肌原位游离移植的模型,评价术后肌萎缩与肌肉收缩功能的相关性。方法显露、游离大鼠股薄肌,在肌肉起止点处切断肌肉附着部,支配神经入肌点前0.5cm处切断该神经,并夹闭该肌的主要供血动静脉约50min,在此期间将肌肉原位重新缝合固定,并行神经端端吻合,复通肌肉血循环。分别在术后不同时段观测肌肉萎缩和肌肉收缩功能的相关指标,并比较其相关性。结果成功构建了吻合血管神经的大鼠股薄肌游离移植动物模型,各分组大鼠成活良好。肌肉移植后,肌湿重维持率先降低后增加,术后第4周时最低,为59.3±5.2%,术后晚期时仍低于对照组的水平(p<0.05);肌纤维横截面积呈现相同的变化趋势。计算术后移植肌肉的最大单或强直收缩力的维持率,术后早期(术后1～3周,失神经期),肌肉功能维持率下降较快,3周时最大单收缩力仅存对照侧的39.53±3.63%,随后逐渐上升,至术后30周时恢复为正常对照的83.16±8.19%;而最大强直收缩力则分别降至39.09±5.07%,然后恢复至86.74±2.88%。结论所构建的吻合血管神经的大鼠股薄肌游离移植动物模型符合研究需要;肌肉移植后肌湿重维持率和肌细胞横截面积先呈现典型肌萎缩后表现,后随神经的再支配,萎缩逐渐好转,但至术后30周时仍未恢复到术前对照组水平;肌湿重维持率和肌细胞横截面积的变化具有较好的一致性,与肌肉功能的变化具有良好的相关性。肌肉萎缩是游离肌肉移植后功能降低的主要原因之一,从蛋白质代谢角度出发,移植后肌肉内蛋白含量尤其是收缩蛋白含量的变化,是肌萎缩与肌肉功能的降低密切相关的重要联系点。

Objective The purpose of this study was to establish an animal model of free muscle transfer with nerve anastomosis using rat gracilis muscle and evaluate some related indexes for muscle atrophy. Methods The gracilis muscle was orthotopic transferred in adult tat to establish the animal model. According the different time after free muscle transfer, muscle weight was measured and compared to that of the control side which had no operation, so did the transaction areas of muscular fiber using NIH Image J software following HE staining. Then muscular function including maximum strength of single contraction and tetanus was recorded using a multiple function physiological recording device. Results Fifty-four SD rats with an average weight of 250±25 g were operated successfully, and animal model of of free muscle transfer with nerve anastomosis was available. Muscle wet weight reservation rate （muscle weight of operative side / muscle weight of control side ×100 %） had a dramatically decrease in the first 4 weeks following the operation and increased gradually from then on, but remained lower compared with the control （p 〈0.05）. Transaction areas of muscular fiber at different stage postoperatively were calculated and exhibited a similar change with that of muscle wet weight. Then muscular function including maximum strength of single contraction and tetanus was successfully recorded using a multiple function physiological recording device. The recovery ratio was consistent with these index for muscular atrophy mentioned above. Conclusion Animal model of of free muscle transfer with nerve anastomosis using rat graeilis muscle was easy and stable. Muscle wet weight reservation rate and transection area of muscle fiber are better indexes for muscle atrophy following free transfer, according the results of muscle function.