Melatonin-loaded chitosan nanoparticles endows nitric oxide synthase 2 mediated anti-inflammatory activity in inflammatory bowel disease model

Inflammatory Bowel Disease (IBD) is a complex inflammatory condition arising due to interactions of environmental and genetic factors that lead to dysregulated immune response and inflammation in intestine. Complementary and alternative medicine approaches have been utilized to treat IBD. However, chronic inflammatory diseases are not medically curable. Hence, potent anti-inflammatory therapeutic agents are urgently warranted. Melatonin has emerged as a potent anti-inflammatory and neuroprotective candidate. Although, it?s therapeutic efficacy is compromised due to less solubility and rapid clearance. Hence, we have synthesized melatonin loaded chitosan nanoparticle (Mel-CSNPs) to improve drug release profile and evaluate its in-vitro and in-vivo therapeutic efficacy. Mel-CSNPs exhibited better anti-inflammatory response in an in-vitro and in-vivo IBD model. Significant anti-inflammatory activity of Mel-CSNPs is attributed to nitric oxide (NO) reduction, inhibited nuclear translocation of NF-kB p65 and reduced IL-1 beta and IL-6 expression. In-vivo biodistribution study has shown a good distribution profile. Effective in-vivo therapeutic efficiency of Mel-CSNPs has been confirmed with reduced disease activity index parameters and inhibited neutrophilic infiltration. Histological evaluation has further proved the protective effect of Mel-CSNPs by preventing crypt damage and immune cells infiltration against Dextran Sodium Sulphate induced insults. Immuno-histochemical analysis has confirmed anti-inflammatory action of Mel-CSNPs with reduction of inflammatory markers, Nitric Oxide Synthase-2 (NOS2) and Nitrotyrosine. Indeed, this study divulges anti-inflammatory activity of Mel-CSNPs by improving the therapeutic potential of melatonin.