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

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.

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.

The final body weight of the HD group was significantly lower than that of the other groups (P = 0.011), and urinary protein excretion in the HD group was significantly higher than in the other groups (P = 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 (P < 0.05). CD68/SR-D1 antibody levels in the HD group were significantly increased (P < 0.050). Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling and Bax positive cells in the HD group were higher than in other groups (P < 0.05), while Bcl positive cells were fewer (P < 0.05).

High-dose consumption of Chaga mushrooms may cause kidney damage due to its high oxalate content.