The effect of sciatic nerve injection of dexmedetomidine on the nociceptive behavior and spinal c-fos expression in formalin mice / 重庆医学

ABSTRACT

Objective To investigate the effect of sciatic nerve injection of dexmedetomidine on the nociceptive behavior and spi-nal c-fos expression in formalin mice .Methods Adult male Kunming mice ,20-25 g ,were divided into 4 groups randomlymice in group A and D were given an injection of NS (10 μL) and 0 .1 μg dexmedetomidine in 10 μL adjacent to the right sciatic nerve , sepretely .Mice in group B received intacutaneous injection of 10μL formalin(5% ) in the right hindpaws .Mice in group C were giv-en an injection of 0 .1 μg dexmedetomidine in 10 μL adjacent to the right sciatic nerve 15 min before formalin injection in the right hindpaws .Paw licking/biting time was counted every 5 min for an hour after hindpaw injections ,calculated pain score .1 hour after behavior tests ,the L4-5 of spinal cord were harvested to immunofluorescence for c-fos expression in the dorsal corn of spinal cord . Results Mice in group A、C and D showed no obvious foot licking/biting behaviors and a low level of c-fos expression in the dorsal corn of spinal cord .Compared with group A ,mice in group B displayed obvious two phases foot licking/biting behaviors(P<0 .05 , both in Phase Ⅰ and Phase Ⅱ) and a significant increasing expression of c-fos(P<0 .05) .Compared with group B ,dexmedetomi-dine injected to the adjacent of right sciatic nerve decreased the pain score and spinal c-fos expression in goup C(P<0 .05) .Conclu-sion Injection of dexmedetomidine to the right sciatic nerve alleviated intraplantar injected formalin-induced acute inflammatory pain ,and reduced the expression of spinal c-fos protein .