The effect of L-arginine and ascorbic acid on the visceral fat and the concentrations of metalloproteinases 2 and 9 in high-fat-diet rats

Introduction: L-arginine (L-arg) and vitamin C supplementation may decrease fat accumulation and have a favourable effect on carbohydrate metabolism. This is partly caused by matrix metalloproteinases (MMPs), which are involved in adipocyte development and remodelling. Our study evaluated the effects of L-arg and vitamin C supplementation on the content of visceral fat (VF%), activity of MMPs, and insulin resistance (IR) in rats fed a high-fat diet (HFD). Material and methods: The experiment was performed using 48 Wistar rats divided into four groups: Group 1 was fed a standard diet, Group 2 a HFD, Group 3 a HFD supplemented with L-arg (A), and Group 4 a HFD supplemented with L-arg and vitamin C (AC). The animals were euthanized after six weeks. The concentrations of serum glucose, insulin, MMP-2, and MMP-9, as well as IR by Homeostatic Model Assessment (HOMA) and VF% were measured. Results: Statistically significant increases in VF%, MMP-2, MMP-9, insulin, and HOMA-IR levels were observed in the HFD group when compared to the control group. A smaller increase in VF%, insulin, and HOMA-IR was seen in Group 3 (A) and 4 (AC). L-arg supplementation protected against increases in MMP-2 and MMP-9 in Group 3 (A) and 4 (AC). Conclusions: L-arginine could protect from an increase in visceral fat through a change in the activity of MMPs and amelioration of insulin sensitivity in rats fed a HFD. The addition of vitamin C did not improve the effects of L-arginine supplementation. (Endokrynol Pol 2015; 66 (6): 526–532)