Expression of heat shock protein 72 in rat quadriceps muscles following anterior cruciate ligament resection

 This study investigated the expression of heat shock protein 72 (HSP 72) in quadriceps femoris muscle following anterior cruciate ligament (ACL) resection and running training in rats. A group of 15 Wistar strain male rats (10 weeks old) were divided into three groups: sham-operated (S), ACL resection (A), and running training following ACL resection (R). In the A and R groups, the ACL of the right knee was resected using microsurgical techniques. Rats in the R group were subjected to running training for 9 weeks on a motor-driven treadmill for rodents 1 week after ACL resection. At 10 weeks after ACL resection, glycerinated single fibers were prepared from vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), and semimembranosus (SM) muscles. To determine the levels of HSP72 (HSP-inducible) in each muscle, we used the Western blotting technique. HSP72 expression in VL and VM increased following ACL resection (P < 0.05) but not in RF or SM. Exercise training caused an elevation in HSP72 expression in VL and VM. There were no significant changes in HSP72 expression in RF or SM following exercise training. These results suggest that some stress would be generated by ACL resection in VM and VL and might cause atrophy in VM and VL. Received: July 29, 2002 / Accepted: October 18, 2002 Acknowledgments. We especially thank Professor H. Aoki of the Department of Orthopaedic Surgery at St. Marianna University School of Medicine for his encouragement and many valuable comments. We also thank Vice President T. Yoshioka of Aomori University of Health and Welfare for his valuable criticism and advice. This study was supported in part by a Grant-in-Aid for Encouragement of Young Scientists (B) from The Ministry of Education, Culture, Sports, Science and Technology (MEXT) to K.G. Offpring requests to: R. Okuyama