miRNA-22 mediates inflammatory pain behavior via the regulation of Mtf1. (a) Intrathecal injection of Mtf1-siRNA (si-Mtf1) for two consecutive days reversed the CFA-induced increase in Mtf1 mRNA. ∗∗p <0.01 versus Sal+Scr. #p <0.05 versus CFA + Scr. n =6. Data were analyzed with a two-way ANOVA followed by post hoc Tukey test. (b)-(e) Intrathecal injection of si-Mtf1 for two consecutive days reduced thermal hyperalgesia (b) and mechanical allodynia (c) on the ipsilateral paw of CFA-injected mice, but did not affect sensitivity to thermal (d) or mechanical (e) stimuli on the contralateral paw. ∗p <0.05 versus CFA + Scr. n =6. Red arrow, CFA or saline injection. Blue arrows, si-Mtf1 or Scr injection. Data were analyzed with a two-way repeated-measures ANOVA followed by post hoc Tukey test. (f)-(g) Mtf1 overexpression induced by intrathecal injection of Lenti-Mtf1 for two consecutive days induced hypersensitivity to thermal (f) and mechanical (g) stimuli. ∗p <0.05, ∗∗p <0.01 versus Vector. n =6. Red arrows indicate Lenti-Mtf1 or the control vector injection. Data were analyzed with a two-way repeated-measures ANOVA followed by post hoc Tukey test. (h) Intrathecal injection of Lenti-Mtf1-shRNA (M-shR) for two consecutive days inhibited the increase in Mtf1 mRNA in CFA-injected mice. ∗∗p <0.01 versus Sal+Vec. #p <0.05 versus CFA + Vec. n =6. Data were analyzed with a two-way ANOVA followed by post hoc Tukey test. (i)-(l) Intrathecal injection of Lenti-Mtf1-shRNA (Mtf1-shRNA) for two consecutive days alleviated thermal hyperalgesia (i) and mechanical allodynia (j) induced by CFA injection in the ipsilateral paw, but sensitivity was unchanged in the contralateral paw (k)-(l). ∗p <0.05, ∗∗p <0.01 versus CFA + Vector. n =6. Red arrow, CFA or saline. Blue arrows, Mtf1-shRNA or Vector. Data were analyzed with a two-way repeated-measures ANOVA followed by post hoc Tukey test. (m)-(n) Intrathecal injection of si-Mtf1 inhibited the pain hypersensitivity induced by miRNA-22 overexpression by its mimic (22-mics). ∗p <0.05, ∗∗p <0.01 versus 22-mics. n =6. Red arrow, 22-mics injection. Blue arrows, si-Mtf1 injection. Data were analyzed with a two-way repeated-measures ANOVA followed by post hoc Tukey test. (o), (p) Intrathecal injection of Mtf1-shRNA attenuated the thermal hyperalgesia (o) and mechanical allodynia (p) induced by Lenti-22. ∗p <0.05, ∗∗p <0.01 versus Lenti-22. n =6. Red arrow, Lenti-22. Blue arrows, Mtf1-shRNA. Data were analyzed with a two-way repeated-measures ANOVA followed by post hoc Tukey test.