Role of Melatonin in Ameliorating the Harmful Effects of Tramadol on the Frontal Cortex of Adult Male Albino Rat (Histological and Immunohistochemical Study)

Introduction: Tramadol is the foremost utilized opioid in moderate to severe pain. Previous studies reported changes in the rat’s brain after either oral or intraperitoneal tramadol administration. Melatonin ‘neurohormone’ has antioxidant and anti-apoptotic effects on the brain.
Aim of the Work: This work aimed to assess the role of melatonin in ameliorating the harmful impacts of tramadol on the frontal cortex of adult male albino rat.
Materials and Methods: forty adult male albino rats were used, their ages ranged from 6-8 months and their weight ranged from 180-200gm. Rats were equally distributed for four groups: Group I (control group): Rats were divided into two subgroups: Ia: rats were kept without any treatment for thirty days and group Ib: rats received intraperitoneal injection of 0.1 mL of 0.9% saline and 2% ethanol daily for thirty days. Group II (Melatonin group): each rat was intraperitoneally injected of 10mg/kg/day of melatonin for thirty days. Group III (Tramadol group): each rat received 50mg/kg/day tramadol orally by orogastric tube for thirty days. Group IV (Tramadol+ Melatonin group): each rat was injected with melatonin and received oral tramadol as in the groups II and III respectively for thirty days.
Results: Tramadol administration resulted in disarrangement of the grey matter layers of rats’ frontal cortices, depletion of glycogen and synaptophysin of neural cells with increased apoptosis and astrocytosis. However, concomitant administration of melatonin with tramadol showed regular structure of rats’ frontal cortices with attenuated neural apoptosis, proper contents of glycogen, synaptophysin and astrocytes.
Conclusion: Melatonin has a good protective effect against the harmful impacts of tramadol on the frontal cortex of adult male albino rat.