Modulatory Role of Melatonin on the Structure of Hard Palatal Mucosa of Aged Rats

Introduction: Aging greatly diminishes the ability of oral tissues to withstand various types of functional insults, and reduces cell regeneration. Hence, anti-oxidation is mandatory to preserve oral tissues especially while aging. Melatonin is an anti-oxidant with established potential in hindering age-related changes. Aim: to evaluate the extent of anti-oxidant and anti-inflammatory potentials of melatonin on aged hard palatal tissues of rats. Materials & Methods: twenty-one Albino rats 200-250 gms each, were used in this study. They were equally divided into 3 groups; Control Young Gp: 6 months of age, Control Senile Gp:18 months of age, and Melatonin Gp: 18 months of age. After 8 weeks, rats were sacrificed by high dose of anesthesia. The hard-palatal mucosae of all rats were separated and processed for histologic examination by H&E, Masson Trichrome stain, and immuno-histochemical staining by Anti-PCNA, then examined by light microscopy. Results: the control senile Gp showed statistically significant increase in vacuolated epithelial cells and area percentage of mature collagen fibers, as well as statistically significant reduction in PCNA-positive cells and apparent reduction of epithelial thickness. On the other hand, the melatonin Gp displayed statistically significant increase in PCNA-positive cells, area percentage of immature collagen fibers, while significant decrease in No. of vacuolated epithelial cells and apparent increase of epithelial thickness.
Discussion: Aging resulted in deteriorated regeneration, enhanced apoptosis, with reduced cellularity and vascularity. On the other hand, melatonin greatly improved cellular proliferation, reduced apoptosis, enhanced CT tissue regeneration and collagen production. As well as reduction in inflammatory cells.