The Co-administration of Nicotine/ Marijuana and Morphine Changes Proinflammatory Cytokines in Rats

Background: Simultaneous co-consumption of abused substances is common among drug users. This study examined the effects of co-administration of marijuana/ nicotine and morphine on some cytokines in rats. Method: Ninety eight rats were randomly divided into fourteen experimental groups including control (saline 1 ml/kg, i.p.), morphine (1, 3 and 5 mg/kg, i.p.), nicotine (0.5, 2 and 4 mg/kg, i.p.), marijuana (2.5, 5 and 10 mg/kg, i.p.) and the combination groups in which the rats received the combination of either effective or sub-effective doses of nicotine/ marijuana and morphine. Inflammation was induced via formalin injection into the left hind paw of all the control and the treated rats. The serum concentrations of some cytokines (TNF-ɑ, IL-1, and IL-6) were measured by using an enzyme-linked immune-sorbent assay (ELISA) technique. Results: A significant reduction in TNF-ɑ, IL-1, and IL-6 concentration was observed in marijuana, nicotine and morphine treated rats. Also, the co-administration of effective doses of marijuana/ nicotine and morphine caused a significant reduction in cytokines, indicating either an additive or a synergistic effect. Conclusion: The clinical application for the combined use of these substances has not been determined yet and further research is needed to clarify the efficacy, safety and tolerability of these combinations in inflammatory process.