Nephroprotective and Antioxidant Effects of King Tuber Oyster Medicinal Mushroom, Pleurotus tuber-regium (Agaricomycetes), on Carbon Tetrachloride-Induced Nephrotoxicity in Male Sprague Dawley Rats

Chronic kidney disease is a health burden worldwide but particularly in sub-Saharan Africa, with dwindling resources as a result of poor commodity export, devaluation of currencies, and corruption that had decreased the average family income and substantially increased the number of persons living on less than $1.90/day. Natural products are part of the healthcare delivery system in that part of the world. This study was conducted to evaluate the protective effects of Pleurotus tuber-regium on the kidneys of rats treated with carbon tetrachloride (CCl4) for 13 weeks. Sixty rats were divided into 6 groups, with 10 animals in each group. Group I (control) received olive oil (3 mL/kg) intraperitoneally twice weekly and were given feed and water ad libitum. Group II received CCl4 (3 mL/kg, 30% in olive oil) twice weekly. Groups III, IV, and V received 100, 200, and 500 mg/kg wild edible P. tuber-regium (33.3% in feed) daily, respectively, in addition to 3 mL/kg CCl4 twice weekly. Group VI received 500 mg/kg P. tuber-regium (33.3% in feed) daily. At the end of 13 weeks, the animals were sacrificed and kidney weights recorded. Serum concentrations of creatinine, urea, and fasting blood glucose were assayed. Malondialdehyde, ascorbic acid, α-tocopherol, superoxide dismutase, catalase, total glutathione, and peroxidase were measured in kidney homogenate. The kidneys were also histologically examined. Administration of CCl4 to rats significantly (P < 0.05) increased the absolute and relative kidney weights from 0.93 ± 0.04 and 0.38 ± 0.02 g in the control group to 1.30 ± 0.04 and 0.58 ± 0.02 g in the treated groups (Groups III, IV, and V), respectively. CCl4 administration increased the concentrations of creatinine, urea, fasting blood glucose, and malondialdehyde from 0.53 ± 0.05 mg/dL, 17.0 ± 1.10 mg/dL, 72 ± 2.80 mg/dL, and 1.40 ± 0.32 μmol/L in the control group to 0.84 ± 0.03 mg/dL, 43.0 ± 6.90 mg/dL, 77 ± 2.2 mg/dL, and 14.0 ± 3.5 μmol/L in the treated groups, respectively. The concentrations of ascorbic acid, α-tocopherol, superoxide dismutase, catalase, total glutathione, and peroxidase decreased significantly (P < 0.05) from 0.41 ± 0.02 mg/dL, 5.15 ± 0.21 μg/mL, 8.49 ± 0.38 units/mL, 75.20 ± 4.57 mU/mL, 1.62 ± 0.03 μg/mL, and 9.74 ± 0.40 mU/mL in the control group to 0.24 ± 0.03 mg/dL, 1.80 ± 0.11 μg/mL, 2.78 ± 0.30 units/mL, 31.9 ± 5.87 mU/mL, 0.36 ± 0.04 μg/mL, and 3.84 ± 0.22 mU/mL in the treated groups, respectively. Photomicrographs showed that P. tuber-regium prevented the fibrosis and tubular and Bowman capsule distortions observed in the CCl4-only group. P. tuber-regium is effective in protecting the kidneys against CCl4-induced damage.