BACKGROUND: Previous research has shown that type 1 interferons (IFN), such as IFN-α and IFN-ß, possess antiviral and antinociception effects. Elevated levels of microRNA-29a (miR-29a) have been observed during inflammatory pain, and as miR-29a targets the type 1 IFN receptor (IFNR1), our study aimed to investigate the involvement of miR-29a, type 1 IFN, and IFNR1 in inflammatory pain. METHODS: Inflammatory pain was induced in male rats using complete Freund's adjuvant (CFA). The changes in miR-29a, IFN-ß, and IFNR1 were measured on Days 2, 3, 5, 7, and 10 post-CFA injection and expression of IFNR1, phospho-ERK (phosphorylated extracellular signal-regulated kinase) (p-ERK), extracellular signal-regulated kinase (ERK), and IFN-stimulated gene 15 (ISG15) were measured in rats that received an miR-29a inhibitor or miR-29a mimic. RESULTS: Our results demonstrated elevated miR-29a expression (CFA 3 days: mean difference [95% confidence interval, CI]: 0.860 [0.657-1.062]
CFA 5 days: mean difference [95% CI]: 1.120 [0.917-1.322], CONCLUSIONS: Inhibiting miR-29a expression attenuates inflammatory pain by modulating IFNR1, ISG15, and p-ERK expression, highlighting the interactive roles of miR-29a and IFN-ß in the regulation of inflammatory pain.