Hydrolyzed Collagen from Salmon Skin Mitigates L-NAME-Induced Hypertension in Rats by Attenuating Oxidative Stress and Inflammation and Improving Vascular Remodeling

This study aimed to investigate whether hydrolyzed collagen (HC) derived from salmon skin could attenuate blood pressure and vascular damage in Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Hypertension was induced in rats by the oral administration of L-NAME (40 mg/kg/day) for eight weeks, while HC in two doses (50, 450 mg/kg) or enalapril at 10 mg/kg dissolved in water were concurrently administered via oral gavage for the last four weeks. Treatment with HC (450 mg/kg) and enalapril resulted in a reduction in systolic blood pressure, oxidative stress markers, and inflammatory cytokines. Production of serum nitric oxide (NO) was also increased, contributing to better aortic function. Histopathological analysis confirmed these changes, showing enhanced progression in the aorta structure. Vascular function was improved, as evidenced by significantly higher relaxation responses to acetylcholine (ACh) in the presence or absence of endothelium. These findings indicate that HC effectively lowered the blood pressure in hypertensive rats, potentially through mechanisms involving the modulation of oxidative stress and the expression of nitric oxide, reducing vascular inflammation and remodeling, hence enhancing vascular function.