Abstract:【Abstract】Objective To study the effect of morphine combined with buprenorphine in different doses on pain behavior of bone cancer in rats. Methods 60 healthy adult female Wistar rats were randomly divided into sham operated group (1 mL of 0.9% sodium chloride solution subcutaneously), morphine group (10 mg/kg of morphine subcutaneously), combined group 1 (10 mg/kg of morphine subcutaneously combined with 20 μg/kg of buprenorphine), combined group 2 (10 mg/kg of morphine subcutaneously combined with 40 μg/kg of buprenorphine), combined group 3 (10 mg/kg of morphine subcutaneously combined with 60μg/kg buprenorphine), 12 rats in each group. All of rats were treated for one week. After 2 weeks of modeling, the experiments of thermal sensitivity, mechanical sensitivity and tail flick were carried out every day for 1 week. ResultsThe thermal pain threshold of morphine group was significantly higher than that of sham operation group (P＜005) on day 14, and there was no significant difference between the two groups on day 57 (P＞005). The thermal pain threshold of combination group 1 and combination group 3 was significantly higher than that of sham operation group on day 13, and that of combination group 1 and combination group 3 was lower than that of morphine group on day 23 (P＜005) and combination group 47 (P＜005). Compared with the sham operation group, there was no significant difference in the thermal pain threshold between the combined group and the sham operation group (P＞005). With the prolongation of administration time, the mechanical threshold and anti injury threshold of morphine group and each combination group decreased significantly (P＜005). The mechanical threshold and anti injury threshold of sham operation group at different times had no significant difference (P＞005). The mechanical threshold and anti injury threshold of morphine group and each combination group at different times were significantly higher than those of sham operation group (P＜005). There was no significant difference in mechanical pain threshold and anti injury pain threshold between the combined group 1, 2 and 3 and the morphine group (P＞005). Conclusion Morphine combined with buprenorphine of different doses has the same analgesic effect on bone cancer pain rats, and can delay the occurrence of morphine tolerance.
