Suppressing Effects of Docosahexaenoic Acid-Containing Diets on Oxidative Stress and Fibrosis in 5/6 Nephrectomized Rats.

KEY POINTS: Increased albuminuria on 5/6 nephrectomized rats, as reported earlier, is attenuated by arachidonic acid–containing and docosahexaenoic acid (DHA)–containing diets. This study established that DHA affects both oxidative stress and fibrosis in the kidney. DHA suppressed the oxidative stress and fibrosis, hence suppressing the progression of renal failure. BACKGROUND: Urinary albumin excretion gradually increases after nephrectomy, which eventually progresses toward renal failure. Our previous study had reported that arachidonic acid (ARA)–containing or docosahexaenoic acid (DHA)–containing diet attenuates the increasing urinary albumin excretion. This study aimed to investigate the effects of ARA-containing or/and DHA-containing diets on oxidative stress and fibrosis that cause kidney injury in 5/6 nephrectomized rats. METHODS: Sprague–Dawley rats were randomly divided into control group, ARA group, DHA group, and ARA+DHA group. Rats underwent 5/6 kidney removal and were fed ARA-containing or/and DHA-containing diet each five groups continuously for 4 weeks. We collected urine, plasma, and kidney samples 4 weeks after surgery and investigated the effects of ARA-containing and DHA-containing diets on oxidative stress, inflammation, and fibrosis in the kidney. RESULTS: Urinary albumin excretion, indoxyl sulfate, reactive oxygen species, TNF-α levels, and fibrosis in the kidney were all increased on nephrectomy; however, they were attenuated after feeding the rats with DHA-containing diet. CONCLUSION: One possible mechanism of preventing chronic renal failure would be the suppression of indoxyl sulfate accumulation, oxidative stress, and kidney fibrosis arising due to nephrectomy. The results collectively suggested that DHA-containing diets can suppress the progression of renal failure.