Objective: To investigate the effect of warm acupuncture on chondrocyte cytoskeleton protein Rho associa-ted protein kinase (ROCK)/ monopherine domain kinase 1 (LIMK1)/Cofilin signaling of synovial tissue of the knee-joint in knee osteoarthritis (KOA) rats, so as to explore its mechanisms underlying improvement of KOA.
Methods: One hundred-twenty SD rats (half male and half female) were randomly divided into 5 groups: normal control, model, acupuncture, moxibustion and warm acupuncture, with 24 rats in each group. The KOA model was established by injection of 4% Papain (0.25 mL/kg) into the right knee cavity on day 1, 3 and 7. Rats in the acupuncture, moxibustion and warm acupuncture groups were treated with manual acupuncture, moxibustion and warm acupuncture stimulation of "Neixiyan"(EX-LE4), "Waixiyan"(EX-LE5) and "Zusanli"(ST36), respectively for 20 min, once a day for 21 days. The volume of the right knee-joint was measured by using drainage method and its width measured using a vernier caliper. The histopathological changes of the right knee cartilage were observed after H．E. stain, and scored (0 to 14 points) with reference to Markin's methods. The expression levels of ROCK, Cofilin, phospho-Cofilin, LIMK1 and phospho-LIMK1 proteins of the right knee synovial tissue were detected by Western blot.
Results: After modeling, the width and the volume since day 6 of the right knee-joint and Markin score of the cartilage, as well as the expression levels of ROCK, phospho-Cofilin, and phospho-LIMK1 proteins were significantly increased in the model group in contrast to the normal control group (P<0.05，P<0.01). Following the interventions, the width and the volume since day 12 of the right knee-joint and Markin score of the cartilage, as well as the expression levels of ROCK, phospho-Cofilin, and phospho-LIMK1 proteins were reversed in the three treatment groups (P<0.05). The effect of warm acupuncture was significantly superior to that of both simple acupuncture and simple moxibustion in decreasing the width and the volume since day 15 of the right knee-joint and Markin score of the cartilage, as well as in down-regulating the expression levels of ROCK, phospho-Cofilin and phospho-LIMK1 proteins (P<0.05). No significant differences were found between the acupuncture and moxibustion groups in deceasing all the aforementioned indexes (P>0.05)．.
Conclusion: Acupuncture, moxibustion and warm acupuncture can reduce arthritic injury in KOA rats, which is closely associated with their effects in down-regulating the expression of chondrocyte cytoskeletal proteins ROCK, phospho-Cofilin and phospho-LIMK1. The efficacy of warm acupuncture is evidently superior to that of simple acupuncture and simple moxibustion.
Keywords: Acupuncture; Cartilage degeneration; Chondrocyte cytoskeletal proteins; Knee osteoarthritis; Moxibustion; Warm acupuncture.