Effects of Dandelion Extract on the Proliferation of Rat Skeletal Muscle Cells and the inhibition of a Lipopolysaccharide-lnduced Inflammatory Reaction

Background: Dandelion is commonly used in traditional Chinese medicine with several active compounds found in extracts. It has a variety of pharmacological effects, such as a reduction in swelling and inflammation, and detoxification. The mechanism by which dandelion extract inhibits the inflammatory response in skeletal muscle cells remains unknown; therefore, the aim of this study was to investigate the effects of dandelion extract root on the proliferation of skeletal muscle cells and the alleviation of lipopolysaccharide (LPS)-induced inflammatory response in vitro. Methods: Rat skeletal muscle cells were isolated from Sprague-Dawley rat and cultured in vitro which were cultured in basal medium, or medium containing LPS or dandelion extract. Cell counting kit-8 (CCK-8) was employed to measure cell proliferation; meanwhile, the optimal concentration of dandelion extract and treatment time were selected. Crystal violet staining was used to detect the proliferation of muscle cells. Western blotting analysis was used to detect the levels of inflammatory factors, myogenic factor, and p-AKT protein expression. Results: The optimal concentration and treatment time of dandelion extract for the following study were 5 mg/ml and 4 days, respectively. Dandelion extract was found to increase proliferation of rat skeletal muscle cells (t = 3.145, P < 0.05), with the highest effect observed at 5 mg/ml. LPS was found to decrease proliferation of skeletal muscle cells (t = -131.959, P < 0.001), and dandelion extract could against this affection (t = 19.466, P < 0.01). LPS could induce expression of inflammatory factors, including interleukin (IL)-1 beta, IL-6 and tumor necrosis factor (TNF)-alpha (IL-1 beta: t = 9.118, P < 0.01; IL-6: t = 4.346, P < 0.05; TNF-alpha: t = 15.806, P < 0.05), and dandelion extract was shown to reduce LPS-induced expression of IL-1 beta, IL-6 and TNF-alpha (IL-1 beta: t = -2.823, P < 0.05; IL-6: t = -3.348, P < 0.01; and TNF-alpha: t = -3.710, P < 0.01). Furthermore, LPS was also shown to decrease expression of myogenic factor, including myod1 and myogenin (MyoD1: t = 4.039, P < 0.05 and myogenin: t = 3.300, P < 0.01), but dandelion extract was shown to against this effect of LPS (MyoD1: t = -3.160, P < 0.05 and myogenin: t = -3.207, P < 0.01). And then, LPS was found to increase expression of p-AKT protein (p-AKT/AKT: t = 4.432, P < 0.05). Moreover, expression of p-AKT protein was found to decrease, with 5 mg/ml of dandelion extract (p-AKT/AKT: t = -3.618, P < 0.05). Conclusions: The findings indicate that dandelion extract plays an important role in skeletal muscle cells viability regulation, promote cells proliferation by increasing level of p-AKT protein expression, and reduce LPS-induced expression of inflammatory factors, inhibiting the inflammatory response of rat skeletal muscle cells.