Melatonin decreases apoptosis in gastric mucosa during aging

The aging process of tissues is usually accompanied by an increased rate of apoptosis. Although melatonin has been reported to delay aging by scavenging free radicals, its role in the aging of gastric mucosa is not known. In this study, we examined the effects of exogenous melatonin (MLT) on the caspase-dependent apoptosis of gastric mucosa during aging.

A total of 55 young, middle-aged and aged male Wistar-albino rats were used in this study. The rats were divided into control groups, treated with 0.1 mL of phosphate buffered saline (PBS) containing 1% ethanol, and melatonin groups, treated with MLT (10 mg/kg/day s.c., dissolved in 0.1 mL of PBS containing 1% ethanol) for 21 days. Plasma thiobarbituric acid (TBARS) and sulfhydryl (RSH) levels were studied as oxidant-antioxidant parameters. Caspase-3 activity of the gastric mucosal tissue was assayed as an indicator of apoptosis. The p53 protein level of the gastric mucosa was assayed using a p53 pan ELISA.

The plasma TBARS and caspase-3 activity of the gastric mucosa were significantly increased in the aged group. MLT significantly decreased the plasma TBARS levels in all the study groups. MLT also significantly decreased the caspase-3 activity of the gastric mucosa in the aged group (p<0.001). Melatonin had no effect on the p53 expression levels of the gastric mucosa.

In conclusion, our findings suggest that aging gastric mucosa is closely related to a higher apoptosis rate and an increase in caspase- 3 activity. Exogenous MLT might delay aging by decreasing caspase-3 activity.