LncRNA MEG3-TRPV1 signaling regulates chronic inflammatory pain in rats.

Osteoarthritis (OA) is a common osteoarthropathy with chronic inflammatory pain as the core symptom in middle-aged and elderly people. LncRNA MEG3 (Maternally expressed gene 3) is involved in the development of OA via regulation of angiogenesis, which causes the activation and overexpression of transient receptor potential vanilloid type-1 (TRPV1). In this study, we investigated the mechanism of MEG3-TRPV1 signaling in chronic inflammatory pain (CIP) of rat model. Chronic inflammatory pain was modeled using subcutaneous microinjection of complete Freund's adjuvant (CFA) into the left hind paw of rats. We showed that TRPV1 mRNA and protein were significantly increased, while MEG3 mRNA was significantly decreased, in the DRG and SDH of CFA-induced rats. In addition, intrathecal injection of MEG3-overexpressing lentivirus significantly downregulated TRPV1 expression and alleviated chronic inflammatory pain in CFA-induced rats. Treatment with a TRPV1 antagonist also significantly relieved chronic inflammatory pain in CFA-induced rats. In general, our results reveal that MEG3 alleviates chronic inflammatory pain by downregulating TRPV1 expression. These findings may provide new therapeutic targets in the treatment of patients with OA.