Effects Of Acute Exercise And Acupuncture Treatment On Collagen Of Skeletal Muscle Extracellular Matrix

Abstract

PURPOSE: Skeletal muscle ultrastructure and content changes of different collagen types in the rat skeletal muscle extracellular matrix after acute eccentric exercise was measured to elucidate the effects of acupuncture on exercise-induced skeletal muscle damage and remodeling of the skeletal muscle extracellular matrix. METHODS: Eight-week-old Sprague-Dawley rats (n = 96, body wt 220 ± 6.9 g) were randomly assigned to four groups: sedentary control (C), acupuncture control (CA), exercise (E) and acupunctured exercise (EA). Animals were adapted to the environment for 3 days and made to run on a motor-driven treadmill with −16° downhill tracks at a speed of 16 m/min for 90 min. CA and EA rats underwent intervention after exercise. Tissues were collected from the vastus intermedius muscle of the experimental rats immediately, and at 24 hours, 48 hours, 72 hours, and 120 hours after exercise. A transmission electron microscope was used to observe the skeletal muscle ultrastructure, a scanning electron microscope was used to analyze the morphological changes of collagen fibers, and western blotting were used to detect gene and protein expression of type I, II, and IV collagen. All animal experiments were approved by the Animal Welfare and Ethics Committee of Zhengzhou University. RESULTS: Acute eccentric exercise increased collagen fiber expression, whereas acupuncture inhibited it. Scanning electron microscope results revealed that collagen hyperplasia was increased in the skeletal muscle of E rats but not EA rats 120 hours post exercise. mRNA levels of type I and III collagen of E rats were upregulated to a maximal level 24 hours after exercise compared with immediately killed rats (Type I: 3.865 ± 1.181 to 11.651 ± 3.526, p = 0.28; Type III: 1.032 ± 0.270 to 2.657 ± 0.883, p = 0.17). The mRNA levels of type I and III collagen in EA rats significantly increased 48 hours after exercise compared with immediately killed rats (Type I: 1.024 ± 0.359 to 4.537 ± 1.621, p = 0.56; Type III: 0.680 ± 0.251 to 2.334 ± 0.945, p = 0.32). CONCLUSION: Acute eccentric exercise may stimulate increase collagen levels in rat skeletal muscle. Acupuncture altered collagen expression to facilitate the recovery and regeneration of injured skeletal muscle.