Cordyceps cicadae extracts ameliorate renal malfunction in a remnant kidney model

Chronic kidney disease (CKD) is a growing public health problem with an urgent need for new pharmacological agents. Cordyceps cicadae is widely used in traditional Chinese medicine (TCM) and has potential renoprotective benefits. The current study aimed to determine any scientific evidence to support its clinical use. We analyzed the potential of two kinds of C. cicadae extract, total extract (TE) and acetic ether extract (AE), in treating kidney disease simulated by a subtotal nephrectomy (SNx) model. Sprague-Dawley rats were divided randomly into seven groups: sham-operated group, vehicle-treated SNx, Cozaar, 2 g/(kg center dot d) TE SNx, 1 g/(kg center dot d) TE SNx, 92 mg/(kg center dot d) AE SNx, and 46 mg/(kg center dot d) AE SNx. Renal injury was monitored using urine and serum analyses, and hematoxylin and eosin (HE) and periodic acid-Schiff (PAS) stainings were used to analyze the level of fibrosis. The expression of type IV collagen (Col IV), fibronectin (FN), transforming growth factor-beta 1 (TGF-beta 1), and connective tissue growth factor (CTGF) was detected by immunohistochemistry. Renal injury, reflected in urine and serum analyses, and pathological changes induced by SNx were attenuated by TE and AE intervention. The depositions of Col IV and FN were also decreased by the treatments and were accompanied by reduced expression of TGF-beta 1 and CTGF. In some respects, 2 g/(kg center dot d) of TE produced better effects than Cozaar. For the first time, we have shown that C. cicadae may inhibit renal fibrosis in vivo through the TGF-beta 1/CTGF pathway. Therefore, we conclude that the use of C. cicadae could provide a rational strategy for combating renal fibrosis.