Unexpected Nephrotoxicity in Male Ablactated Rats Induced by Cordyceps militaris: The Involvement of Oxidative Changes

Recently, many nutraceutical products containing the powdered or extracted parts of C. militaris have become available for health care. Due to the increased morbidity and mortality, poisonings associated with the use of herbs have raised the universal attention. Herein, we carried out the 28-day repeated toxicity test in male and female ablactated rats (three weeks old) given C. militaris powder orally at 0 (control), 1, 2, and 3 g/kg per day. Noticeable increments of serum aspartate and alanine aminotransferase (ALT and AST) levels were observed for both sexes, suggestive of weak hepatic toxicity. Nephrotoxicity characterized by tubular epithelium degeneration and necrosis was observed at the high dose, and the male rats were more susceptible to renal toxicity than female rats. In addition, the genes and protein expressions of novel markers of kidney toxicity, such as kidney injury molecule-1 (KIM-1) were enlarged in the renal cortex and the urine. Moreover, C. militaris treatment significantly decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities. However, the ratio of glutathione oxidized form (GSSG)/glutathione reduced form (GSH) was increased by C. militaris treatment. We conclude that dietary contamination with C. militaris may have renal toxicity potentials, at least in part by causing oxidative damage to the kidney.