Down-regulation of miR-140-3p can alleviate neonatal repetitive pain in rats via inhibiting TGF-β3.

MicroRNAs (miRNAs) have been shown to be involved in the pathophysiological processes of pain. At present, the roles and mechanisms of miRNAs in neonatal repetitive pain are largely unknown. In our research, the expression of miR-140-3p was increased in premature infants who received repetitive painful stimuli since admission, and in rat pups after repetitive needlestick stimulation. As a result of behavioral testing, the inhibition of miR-140-3p significantly suppressed abnormal mechanical and thermal hyperalgesia in rats after needlestick. Furthermore, the inhibition decreased the expression of the inflammatory cytokines IL-1β, TNF-α, and IL-6, as well as glucocorticoid receptor expression in rats after needlestick. Using bioinformatic analyses, the 3'-untranslated region of TGF-β3 was predicted to be a target of miR-140-3p. Down-regulation of miR-140-3p significantly promoted the expression of TGF-β3 in vitro and in vivo. Mechanistic investigations revealed that TGF-β3 is a direct target of miR-140-3p, and is involved in the miR-140-3p-mediated effects on neonatal repetitive pain and neuroinflammation. In summary, our current research suggests that down-regulation of miR-140-3p can inhibit painful tactile stimulation of rat pups by inhibiting TGF-β3. Our results suggest that miR-140-3p may provide a new regulatory target for preventing the effects of neonatal repetitive pain.