The mechanism of Qijing Mingmu decoction on cellular senescence of conjunctivochalasis

BACKGROUND: Qijing Mingmu decoction (QJMM), a compound Chinese medicine preparation, which consists of Lycium barbarum, Polygonatum, Ophiopogon japonicus, Poria cocos, Glycyrrhiza, Eclipta prostrata and Ligusticum striatum, has been confirmed to be effective for the treatment of conjunctivochalasis (CCH) in clinic and reduce cellular senescence. However, the underlying mechanism is still unknown. Our previous study revealed that p38-mediated cellular senescence contributed to the pathogenesis of CCH. METHODS: To explore whether p38 might be the potential therapeutic target of QJMM for CCH, CCH fibroblasts were treated with QJMM granule and then the effect of QJMM granule on the expression and promoter activity of p38α was determined by western blot and dual luciferase reporter gene assay, respectively. Meanwhile, the influence of QJMM granule on cell proliferation, oxidative stress, cellular senescence and the expression of the cellular senescence-associated genes were measured by corresponding methods. RESULTS: QJMM granule significantly decreased the protein expression of p38α and p-p38α in CCH fibroblasts in a dose-dependent manner and inhibited p38α promoter activity. QJMM granule as well as the p38 inhibitor SB203580 reduced the level of reactive oxygen species and increased the activity of superoxide dismutase in CCH fibroblasts. QJMM granule and SB203580 promoted cell proliferation and reduced the percentage of SA-β-Gal-positive cells. The mRNA and protein expression of p53 and p21 was remarkably down-regulated by QJMM granule as well as SB203580 and that of SMP30 was up-regulated in CCH fibroblasts. CONCLUSIONS: Our findings demonstrated that QJMM granule was effective for alleviating cellular senescence of CCH fibroblasts by p38 MAPK signaling and the followed p53/p21 signaling.