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Background Nonalcoholic steatohepatitis (NASH), a common cause of liver-related morbidity and mortality worldwide, is characterized by inflammation and hepatocellular injury. Our research focuses on lipoprotein-associated phospholipase A2 (Lp-PLA2), an inflammation-related biomarker that has recently garnered interest in the context of NASH due to its potential roles in disease pathogenesis and progression. Methods We established a NASH mouse model using a high-fat diet (HFD) and treated it with sh-Lp-PLA2 and/or rapamycin (an mTOR inhibitor). Lp-PLA2 expression in NASH mice was detected by qRT-PCR. Serum levels of liver function parameters and inflammatory cytokines were detected using corresponding assay kits. We examined pathological changes in liver using hematoxylin-eosin, oil red O, and Masson staining, and observed autophagy through transmission electron microscopy. The protein levels of Lp-PLA2, mTOR, light chain 3 (LC3) II/I, phosphorylated Janus kinase 2 (p-JAK2)/JAK2, and phosphorylated signal transducer and activator of transcription 3 (p-STAT3)/STAT3 were determined by western blotting. Kupffer cells extracted from C57BL/6J mice were treated to replicate NASH conditions and treated with sh-Lp-PLA2, rapamycin, and/or a JAK2-inhibitor to further verify the roles and mechanisms of Lp-PLA2 in NASH. Results Our data indicate an upregulation of Lp-PLA2 expression in HFD-induced NASH mice. Silencing Lp-PLA2 in NASH mice reduced liver damage and inflammation markers (aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), triglycerides (TG), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6)), while increasing IL-10 levels, an anti-inflammatory cytokine. Additionally, Lp-PLA2 silencing decreased lipid and collagen accumulation and promoted autophagy. The beneficial effects of sh-Lp-PLA2 on NASH were enhanced by rapamycin. Furthermore, Lp-PLA2 silencing resulted in the downregulation of the expression of p-JAK2/JAK2 and p-STAT3/STAT3 in NASH mice. Similar results were observed in Kupffer cells treated under NASH conditions; Lp-PLA2 silencing promoted autophagy and repressed inflammation, effects which were potentiated by the addition of rapamycin or a JAK2-inhibitor. Conclusion Our findings suggest that silencing Lp-PLA2 promotes autophagy via deactivating the JAK2/STAT3 signaling pathway, thereby restraining NASH progression. This highlights the potential therapeutic value of targeting Lp-PLA2, adding a new dimension to our understanding of NASH pathogenesis and treatment strategies.

Objective: To verify the feasibility of treating pressure ulcers (PUs) with autologous platelet-rich fibrin-based (PRF) bioactive membrane, both in vitro and in vivo. Method: An animal model using adult male Sprague-Dawley rats was used. Pressure was periodically exerted on the skin to induce localised ischaemia by using an external magnet and transplanted metal disc. After a PU developed, the rats were divided into two groups: a treatment group and a control group. Rats in the treatment group were then treated with PRF bioactive membrane every three days. Results: A total of 20 rats were used in this study. At days three and seven, the PU area in the PRF bioactive membrane-treated group was significantly smaller than that in the control group, and after 14 days of treatment, the PUs in the PRF bioactive membrane treatment group had healed. Haemotoxylin and eosin staining, immunohistochemistry and Western blot results indicated that PRF bioactive membrane induced wound healing by increasing the thickness of the regenerated epidermis and by upregulating vascular endothelial growth factor expression. Further, we found that different concentrations of rat autologous PRF soluble factors extraction components could significantly promote rat aortic endothelial cell proliferation, wound healing and migration ability in vitro. Conclusion: Overall, results indicate that PRF bioactive membrane promotes PU healing in rats. Thus, it may represent a natural and effective wound-healing tool for use in the treatment of clinical skin PUs in humans in the future.