Kidney Injury Induced by High-Dose Chaga Mushroom Consumption: Experimental Evidence in a Rat Model.

Abstract

BACKGROUND: Kidney damage can result not only from the overproduction of endogenous oxalate but also from excessive dietary intake. This study investigated whether oxalate-rich Chaga mushroom induces kidney injury. METHODS: Wistar rats were allocated to three groups based on dosese extrapolated from a previously reported clinical case. The standard-dose group received Chaga mushroom powder at 1,281.6 mg/kg body weight (equivalent to oxalate at 183 mg/kg body weight), and the high-dose (HD) group at 3,844.8 mg/kg body weight (equivalent to oxalate at 549 mg/kg body weight); the control group received no supplements. The study assessed chronic kidney injury by evaluating renal function, histopathology, oxidative stress, and apoptosis via immunohistochemistry and immunoblot assay. RESULTS: The final body weight of the HD group was significantly lower than that of the other groups (= 0.011), and urinary protein excretion in the HD group was significantly higher than in the other groups (= 0.001). Histopathologic examination revealed oxalate crystal deposition and tubular injury in the HD group. Oxidative stress markers, including 8-hydroxy-2'-deoxyguanosine levels in serum, urine, and kidney tissue from the HD group, were significantly elevated compared to other groups (< 0.05). CD68/SR-D1 antibody levels in the HD group were significantly increased (< 0.050). Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling and Bax positive cells in the HD group were higher than in other groups (< 0.05), while Bcl positive cells were fewer (< 0.05). CONCLUSION: High-dose consumption of Chaga mushrooms may cause kidney damage due to its high oxalate content.