The ameliorating effect of melatonin hormone on the nicotine - induced tissue damage in male rats

Abstract

The present study aimed to investigate whether melatonin (the pineal gland hormone) could ameliorate tissue damage caused by nicotine in male Sprague Dawley (SD) rats. For this purpose 75 mature male Sprague Dawley (SD) rats weighing 140-160 g obtained from the Animal House Colony of Abou Rawish, Giza, Egypt were used. The study was carried out at the Physiology department, Faculty of Veterinary Medicine, Cairo University during the period from July to August 2018. The rats were fed on a standard granulated rat ration which contains crude protein not less than 21%, crude fat not less than 4.43% and crude fibers not more than 2.94%. The rats were maintained in a special room, with natural ventilation with 12 hrs. Light / dark cycle at room temperature (22-25˚C) and humidity (60-65%). Water and feed were available ad libitum. The study was carried out for 21 successive days. Before starting all animals were subjected to acclimation for 2 weeks. The rats were randomly divided into 5 equal groups with 3 replicate cages having 5 rats in each and treated as follow: The 1st group (control group) received daily I/P injection of 1% ethanol in saline. The 2nd group (nicotine group) received daily I/P injection of nicotine hydrogen bitartarate at a dose of 0.6 mg/kg bwt. The 3rd, 4th and 5th groups (nicotine and melatonin groups) received daily I/P injection of the same dose of nicotine followed 30 minutes later by I/P injection of melatonin at a dose of 1, 5 or 10mg/kg bwt, respectively. All treatments were given 2 hrs. before sunset.