Relationship Between Muscle Tension And Recovery Of Function During Muscle Transfer In A Rabbit Model

ObjectiveTo explore the relationship between muscle tension and recovery of function duringmuscle transfer，and attempt to demonstrate that the sarcomere Length is also a reliable indicatorof muscle tension, which can be used to optimize muscle function.Methods22male SD Rabbit, SPF grade, weighing (1.65±0.10) kg, were used. the flexor digitorumlongus muscle was cut distally and transferred and woven into the tibialis anterior tendon.Resting and transferred Muscle length,Sarcomere lengths were measured in the interoperation；Ankles were then immobilized for3weeks in75°flexion，2Rabbits died within3weeks of theexperiment. Both flexor digitorum longus muscles were harvested and muscle contractivecapacity and muscle wet weight maintenance rate, architectural analysis were detected3weeksand3months after operation, and10rabbits were killed at each time point.ResultWith the increase of the intraoperative sarcomere length and muscle length relative ratio,the value of muscle contractive capacity and muscle wet weight maintenance rate after3weeksand3months increases primarily and then decreased; the correlations among them prove to bequadratic curve through SPSS13.0Curve Estimation (R~2value in the0.590-0.829range, F valuein the5.040-16.977range, P <0.05); The peaks of curve of muscle contractive capacity andmuscle wet weight maintenance rate after3weeks are about at muscle length relative ratio1.04and the sarcomere length3.00μm, The peaks of curve of muscle contractive capacity and musclewet weight maintenance rate after3months are about at muscle length relative ratio1.08and thesarcomere length3.20μm. Sarcomere length increases as muscle length relative ratio increases,the relationship between them prove to be linear correlation after linear regression analysis ((r~2=0.980,F=902.815, P=0.000), linear regression equation: y~∧=0.573+0.158x. ConclusionFollowing a long-term recovery period, a muscle set with increased tension contracts withbetter recovery of muscle function and negligible adverse effects to muscle fibers; Musclesproduce maximum tensions at just over resting length, at about108%of resting length. Thesarcomere length can be used as a characterization of muscle tension and proved to be anexcellent predictor of active muscle force generated.