Introduction: Recent investigations have indicated the potential therapeutic role of cannabinoid type 2 (CB2) receptors in various inflammatory-related disorders. However, the role of these receptors has not been studied in skin flap models previously. In this study, we aimed to evaluate the possible involvement of CB2 receptors in the anti-inflammatory effects of sumatriptan and improvement of the random-pattern skin flap survival in rats.
Methods: In a controlled experimental study, 36 male Wistar rats were randomly divided into six study groups (n = 6 per group). Two doses of sumatriptan (0.1 and 0.3 mg/kg) were administered intraperitoneally (i.p) 30 minutes before harvesting the flap tissue. In a separate group, SR144528 (a selective CB2 receptor inverse agonist) was injected before the most effective dose of sumatriptan to determine the possible involvement of CB2 receptors in its action. Histopathological examinations, the expression level of CB2 receptors (by western blot analysis), and IL-1 and TNF-α concentrations (ELISA) were explored in the skin flap samples.
Results: Sumatriptan 0.3 mg/kg remarkably enhanced the skin flap survival in all macroscopic and microscopic investigations compared to the control group (P <0.001). IL-1 and TNF-α levels were significantly attenuated (P <0.001), and the expression of CB2 receptors in skin cells was amplified in rats treated with sumatriptan 0.3 mg/kg (p <0.05) compared to the control group. However, the administration of SR144528 (2 mg/kg) nullified all the protective effects of sumatriptan (0.3 mg/kg).
Conclusion: We discovered that CB2 receptors play a crucial role in the favorable effects of sumatriptan on skin flap survival as a novel mechanism of action. So, targeting these receptors seems to be a dependable method in skin flap surgeries to ensure its survival and prevent tissue necrosis. Further experimental and clinical investigations are needed to ensure the safe clinical application of this method.
Inducible nitric oxide synthase (iNOS) activity promotes ischaemic skin flap survival
