Low-Molecular-Mass Fragments of Collagen Improve Parameters Related to Mass and Inflammation of the Adipose Tissue in the Obese Rat

Research background. Despite clearly recognized links between increased body mass and increased risk for various pathological conditions, therapeutic options to treat obesi-ty are still very limited. The aim of the present study is to explore the effect of low -molec-ular-mass collagen fragments obtained from the scales of Antarctic wild marine fish on rats' visceral and subcutaneous white adipose tissue in a high-calorie diet-induced obe-sity model.Experimental approach. The study was conducted on outbred rats, which were divided into 3 experimental groups: (i) control, consuming standard food (3.81 kcal/g), (ii) obese group, consuming a high-calorie diet (5.35 kcal/g), and (iii) obese group, consuming a high-calorie diet (5.35 kcal/g) with intragastric administration of low-molecular-mass col-lagen fragments (at a dose 1 g/kg of body mass during 6 weeks). Low-molecular-mass collagen fragments were obtained by a procedure that included collagen extraction from fish scales and enzymatic hydrolysis with pepsin. Apart from hematoxylin and eosin stain-ing, fibrosis level was assessed by histochemical Van Gieson's trichrome picrofuchsin stain-ing, and mast cells were analysed by toluidine blue O staining.Results and conclusions. Group treated with low-molecular-mass fragments of collagen exhibited decreased rate of mass gain, relative mass, area occupied by collagen fibre of both visceral and subcutaneous adipose tissue, and cross-sectional area of both visceral and subcutaneous adipocytes. Treatment with low-molecular-mass fragments of collagen reduced the infiltration of immune cells, number of mast cells and their redistribution back to the septa. This was also accompanied by a decreased number of the crown-like struc-tures formed by the immune cells, which are markers of chronic inflammation that accom-panies obesity.Novelty and scientific contribution. This is the first study that reports the anti-obesity effect of low-molecular-mass fragments produced as a result of controlled hydrolysis of collagen from the scales of Antarctic wild marine fish in the in vivo model. Another novel-ty of this work is the observation that the tested collagen fragments not only reduce the body mass, but also improve the morphological and inflammatory parameters (decrease in the number of crown-like structures, immune cell infiltration, fibrosis and mast cells). Altogether, our work suggests that low-molecular-mass collagen fragments are a prom-ising candidate for amelioration of some comorbidities linked to obesity.

Automated summary

This study explores the effect of low-molecular-mass collagen fragments obtained from the scales of Antarctic wild marine fish on rats' adipose tissue in a high-calorie diet-induced obesity model. The results show that the treatment with low-molecular-mass collagen fragments reduces body mass, improves morphological parameters, and decreases inflammation in obese rats.