Effects of warm acupuncture on apoptosis of chondrocytes and MiR-27a-mediated PI3K/AKT/mTOR signaling pathway in a rat model of knee osteoarthritis / 中华物理医学与康复杂志

ABSTRACT

Objective:To observe any effect of warm acupuncture on chondrocyte apoptosis and the miR-27a-mediated PI3K/AKT/mTOR signaling pathway using a rat model of early knee osteoarthritis (KOA).Methods:Fifty Sprague-Dawley rats were randomly divided into a control group, a model group, a warm acupuncture group, an inhibitor group, and an inhibitor + warm acupuncture group (the combined group), each of 10. Three days before the modeling, both the inhibitor and combined groups were injected with miR-27a inhibitor. Papain was then injected in all groups except the control group to establish the early KOA model. After successful modeling, the combined and warm acupuncture groups were given 30 minutes of warm acupuncture at the medial and lateral Xiyan points daily for 14 days. The model and inhibitor groups were fixed for 30 minutes during those sessions. After the 2 weeks, hematoxylin-eosin staining was used to observe any pathological changes in the cartilage tissue. Terminal deoxynucleoitidyl transferase-mediated nick end labeling was used to detect chondrocyte apoptosis, and enzyme-linked immunosorbent assays were employed to observe the levels of interleukin 1β (IL-1β) and IL-6. Western blotting was used to evaluate the expression of p-PI3K, p-AKT, p-mTOR, PI3K, AKT, mTOR, LC3-II, and Beclin1 proteins in the cartilage tissue, while quantitative real-time polymerase chain reactions detected the content of miR-27a.Results:After the intervention, the morphology of the chondrocytes in the warm acupuncture group had improved significantly compared to the model group, while that of the inhibitor and combined groups was better than among the warm acupuncture group. The rate of chondrocyte apoptosis in the warm acupuncture group was significantly lower than in the model group, while the rates of the inhibitor and combined groups were lower still. There was no significant difference between the inhibitor and the combination group on average. The average expression of IL-6, IL-1β, LC3-II and Beclin1 protein and of miR-27a were significantly lower in the warm acupuncture, inhibitor and combined groups than among the model group, with those of the inhibitor and combined groups significantly lower than among the warm acupuncture group, on average. The average p-PI3K/PI3K, p-AKT/AKT and p-mTOR/mTOR levels of the warm acupuncture, inhibitor and combined groups were significantly higher than those of the model group, with those of the inhibitor and combined groups significantly higher, on average, than among the warm acupuncture group. However, there was no significant difference between the inhibitor group and the combined group in their protein expression and mRNA levels.Conclusions:Warm acupuncture may down-regulate the expression of miR-27a to promote the activation of the PI3K/AKT/mTOR signaling pathway, inhibiting excessive autophagy and apoptosis. That would relieve inflammation and damage, and delay degeneration in early KOA, at least in rats.