Effect of Scrophulariaoxy sepala methanolic extract on tolerance to analgesic effect of morphine in mice with skin cancer

Abstract

Study on the effect of Scrophularia oxysepala methanolic extract on tolerance to the analgesic effect of morphine in mice with skin cancer Introduction: Morphine is one of the most important analgesic agents in the control of cancer pain. Despite its effectiveness, chronically it causes tolerance and dependence Objective: Study on the effect of Scrophularia oxysepala methanolic extract on tolerance to the analgesic effect of morphine in mice with skin cancer. Methods: The study was performed on Albino-Swiss male mice. The mice's hairs was shaved by a shaving machine and a hairbrush,24 hours later mice To induce skin cancer were initiated by a single dose of 7, 12 -dimethyl Benz (a) anthracene (DMBA) (60g/100l acetone/mouse). After 7 days, animals were promoted topically by croton oil (0. 5mg/200l acetone/mouse) twice weekly for period of 25 weeks. The animals were monitored for skin cancer induction. Pain response time was controlled by Hot plate test. Morphine was injected intraperitoneally for 30 days to determine morphine tolerance in healthy and cancerous mice, at a dose of 20 mg/kg and the control group was injected with normal saline . In the other three groups of cancerous mice, in addition to morphine and normal saline, Scrophularia oxysepala was gavaged with daily doses (50, 100, 200mg/kg). Half an hour after injection the reaction time to pain was evaluated. Results: Tolerance appeared in the healthy and cancerous groups at days 9th and 7th respectively. The results were similar to the morphine-treated groups at the dose of 50 mg/kg doses, but the doses of 100 and 200 mg/kg tolerance appeared on days 14 and 17, respectively. Conclusion: The results of this study indicate that tolerance occurs earlier in cancerous animals than in healthy animals and that the Scrophularia oxysepala can reduce morphine tolerance in a dose dependent manner.