Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition mainly characterized by social impairments and repetitive behaviors. An altered intestinal barrier morphology and increased transmucosal leaks have also been implicated in ASD; in fact, comorbidities such as gastrointestinal problems (leaky gut) have frequently been reported in these patients. The regulation of tight junctions (TJs) is essential in maintaining intestinal barrier morphology and in regulating the delicate balance of trafficking between the intestinal lumen and the submucosa. To date, there are no definitive treatments for ASD comorbidities; however, melatonin (MLT) represents a well-validated and tolerated treatment for sleep disorders in ASD patients. The potential beneficial effects of MLT on this disorder have been and continue to be better investigated. In this context, the present study examines the effects of oral MLT administration (10 mg/kg/day for 16 weeks) on the intestinal barrier in BTBR T + Itpr3tf/J (BTBR) mice, a validated ASD model. Morphological analyses of the ileum of these animals reveal modified villus height (Vh), crypt depth (Cd), and Vh-Cd ratios; an inflammatory state; and a decrease in Paneth cells. Moreover, these mice showed altered TJ expression compared to the control animals (C57BL6/J mice). Notably, MLT normalizes morphological indices and TJ expression, consistent with an improved gut barrier morphology. These data collectively suggest that orally administered MLT can promote the remodeling of the intestinal barrier; thus, we can suppose that MLT reduces gastrointestinal barrier leaks. The overall safety and economy of MLT use suggest that this indolamine could be efficacious as an adjuvant therapy to reduce the condition known as leaky gut.