Effect of butorphanol and sufentanil with epidural injections on neurobehavior function in bone cancer pain model rats

Abstract

Objective To observe the effect of different doses of butorphanol and sufentanil repeatedly epidural injected on the neurobehavior function in bone cancer model rats. Methods A PE-530 catheter was inserted into the epidural space of all male Sprague-Dawley rats( not mated, weighting 150-180 g) at L1-2 level. Three days after operation, 64 rats without any motor dysfunction were randomly divided into eight groups(n=8): sham operated group (group C), normal saline with bone cancer pain group (group N), butorphanol groups(group B1, B2, B3)and sufentanil groups(group S1, S2, S3). Bone cancer pain model was constructed in group N, B and S when rats in group C were sham operated. Rats in group C and N were epidurally injected NS 30μl each, and rats in group B1, B2 and B3 were respectively epidurally injected butorphanol 25, 50, 100 μg (all diluted to 30 μl with NS), when rats in group S1, S2 and S3 were respectively epidurally injected sufentanil 1, 2, 4 μg (all diluted to 30 μl with NS) on time per day for 10-14 days after modeling. The neurobehavior paw withdrawal threshold (MWT) of the left hind claw was recorded to observe the changes in pain behavior. The neurobehavior function of rats were recorded by BBB (BASSO, BEATTIE and BRESNAHAN) score and the inclined plane test. Results Compared with group C((67.65±9.29)g), the MWT of the model groups obviously decreased before the first time of injection (N(15.23±2.46)g, B1(16.14±2.28)g, B2(15.42±3.22)g, B3(14.35±2.32)g, S1(15.37±2.11)g, S2(15.22±2.93)g, S3(16.25±2.36)g) (all P 0.05). At 6 h after the forth injection the inclined plane test and the BBB scores of group B3 were obviously decreased compared with group N((34.72±4.56)° and (10.64±1.82) points to (43.15±4.67)° and (14.05±1.78) points (P<0.05)). Conclusion The results provide evidence that repeatedly epidural injection of butorphanol 50 μg or 100 μg or sufentanil 4 μg can reduce the pain of the rats with bone cancer pain. But repeated epidural injection of butorphanol 100 μg can injure the neurological function. Key words: Butorphanol; Sufentanil; Bone cancer pain model; Epidural; Mechanical withdrawal threshold; The inclined plane test; Neurobehavior function