Gastroprotective potential of melatonin versus melatonin loaded niosomes on gastric ulcer healing in rats

The present study was conducted to investigate the therapeutic effects of melatonin and melatonin-loaded niosomes on ethanol-induced gastric lesions. Morphological and biochemical changes associated with each drug were investigated. Seventy apparently healthy female albino rats, weighting about 200–250 g were randomly assigned to 4 experimental groups. The first group (induction group) included 10 rats that were given 1 ml 70 % ethanol and sacrificed after 1 and 1/2 hour. The second group (melatonin-treated group) included 25 rats that were administrated with 2 mg/rat melatonin by gastric tube daily after induction of ulcer by ethanol. Five rats were sacrificed after 3, 7, 14, 21, and 28 days post-treatment. The third group (melatonin-loaded niosomes treated group) consisted of 25 rats that were given melatonin-loaded niosomes in the same dose and route as the third group. Five rats were sacrificed after 3, 7, 14, 21, and 28 days post-treatment. The fourth group (control group) consisted of 10 rats that administrated only the vehicle in a similar dose and route as other groups (5 rats were given 1 ml of saline and the other 5 rats were given 1 ml of niosomes polymer daily via gastric tube). The rats were kept throughout the time of the study and were sacrificed by cervical dislocation at the end of the experiment. Gross lesions were carried out, and ulcer index was calculated for each subgroup. Tissue samples were fixed in 10 % neutral buffered formalin and stained with Hx&E stain for conventional histological examination. Biochemical analysis of tissue homogenate for determination of lipid peroxidation and total antioxidants was performed. Melatonin-loaded niosomes showed early impressive gastroprotection as early as 7 days post-treatment while unloaded melatonin therapy exerted their effects after 14 days respectively. In addition, melatonin-loaded niosomes improved the micro-vascular damages after 14 days compared to the other melatonin-treated group which showed improved gastric alterations after 21 days. Biochemically, the cases of melatonin-loaded niosomes achieved the lowest mean values of lipid peroxidation and highest mean values of total antioxidants compared to other values recorded in case of unloaded melatonin therapy, and these results are in accordance with that of the histopathological findings. © 2016, Springer-Verlag London.