The role of matrix metalloproteinase-1 (MMP1) in LPS-induced degradation of collagen in the calipash of Chinese soft-shelled turtle Pelodiscus sinensis

This study investigated the role of matrix metalloproteinase-1 ( MMP1 ) in the LPS-induced degradation of calipash collagen in Pelodiscus sinensis . Following LPS induction in vivo , the calipash tissue exhibited significant oxidative stress, as indicated by elevated levels of ROS and MDA along with decreased activity of antioxidant enzymes. Meanwhile, the structure of collagen fibers was disrupted, the collagen content declined, and the expression of MMP1 at both the gene and protein levels was significantly up-regulated. Conversely, the expression of collagen biosynthesis–related genes and tissue inhibitor of metalloproteinases-4 was downregulated. In the calipash fibroblasts of P. sinensis cultured in vitro , overexpression of MMP1 aggravated oxidative stress and inhibited the collagen synthesis, while promoting the expression of genes associated with collagen degradation. In contrast, knockdown of MMP1 in vitro enhanced the cellular antioxidant capacity, promoted collagen synthesis–related gene expression, and alleviated LPS-induced collagen degradation. These findings demonstrate that MMP1 acts as a key regulator of collagen metabolic balance under LPS-induced stress. Its upregulation accelerates collagen degradation, while its suppression helps preserve collagen structural integrity. This study provides a theoretical basis for elucidating the molecular mechanism underlying the decline in calipash quality caused by collagen degradation under stress conditions of P. sinensis . These insights are of great significance for developing anti-stress technologies and improving the breeding quality by inhibiting collagen degradation via MMP1. • LPS-induced oxidative stress activates MMP1 in P. sinensis calipash. • MMP1 overexpression disrupts antioxidant capacity, its knockdown preserves it. • Identifies MMP1 as key regulator of collagen metabolic balance.