Role of spinal c-Jun N-terminal kinase signaling pathway in incisional pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of spinal c?Jun N?terminal kinase ( JNK ) signaling pathway in incisional pain in rats. Methods Sixty?three adult male Sprague?Dawley rats, weighing 200-250 g, were randomly divided into 3 groups ( n=21 each) using a random number table incisional pain group ( IP group) , dimethyl sulfoxide ( DMSO) group, and JNK inhibitor SP600125 group ( SP group) . A 1?cm longitudinal incision was made through skin, fascia and muscle of the plantar aspect of the hindpaw in anesthetized rats. In group DMSO, 10% DMSO 10 μl was injected intrathecally at 30 min before surgery. In group SP, SP600125 25 μg (in 10 μl of 10% DMSO) was injected intrathecally at 30 min before sur?gery. Six rats in each group were sacrificed, and the mechanical paw withdrawal threshold ( MWT) and thermal paw withdrawal latency ( TWL) were measured at 24 h before establishment of the model and 2, 6, 24, 48 and 72 h after establishment of the model. After measurement of the pain threshold at 24 h before establishment of the model and 6, 24, 48 and 72 h after establishment of the model, the lumbar segment of the spinal cord was removed for determination of the expression of phosphorylated JNK ( p?JNK) by im?munofluorescence. Results The MWT was significantly lower, the TWL was shorter, and the expression of p?JNK was lower at each time point after establishment of the model than at 24 h before establishment of the model in group IP (P0?05) . Conclusion Spinal JNK signaling pathway is involved in the develop?ment and maintenance of incisional pain in rats.