New indication of Chuankezhi injection for steroid-resistant focal segmental glomerulosclerosis and its mechanism of action

BACKGROUND: Chuankezhi (CKZ) injection is a traditional Chinese medicine (TCM) injection extracted from Chinese herbs Epimedium sagittatum (Yin Yang Huo) and Morinda officinalis (Bai Ji Tian). Studies have shown that CKZ has a positive effect on improving diabetic nephropathy and regulating immune function. Focal segmental glomerulosclerosis (FSGS) is a kind of refractory nephropathy, which has been confirmed as closely associated with immunity. Whether CKZ is effective against FSGS and how it works warrant further study. This study aimed to verify the efficacy of CKZ in rats with steroid-resistant (SR) FSGS and explore its mechanism of action. METHODS: We established an SR FSGS model in male Sprague Dawley (SD) rats by injecting adriamycin into the tail vein. Based on group intervention and comparison, the primary efficacy parameters of FSGS were observed, including general condition, 24-hour urine protein, serum albumin, cholesterol, triglyceride, and renal pathological changes. Network pharmacological analysis and molecular docking were used to predict the mechanism of action of CKZ. Finally, we used quantitative polymerase chain reaction (qPCR) and western blot (WB) to detect messenger RNA (mRNA) expression and protein phosphorylation at specific targets in rat kidney tissue to validate the predicted results. RESULTS: Intramuscular injection of CKZ had a dose-dependent effect in SR FSGS model rats, including lowering urine protein, increasing serum albumin, lowering cholesterol and triglyceride, and treating pathological lesions in the kidney. Network pharmacological analysis and Molecular docking revealed that 5 active components (Icariin, Icariside II, Epimedin C, Icaritin, and Noricaritin) might be the critical components. The findings also revealed that Akt was perhaps the critical target gene, the PI3K-Akt signaling pathway was perhaps the critical pathway, and reversible protein phosphorylation was probably the critical biological process. The qPCR and WB analyses showed that CKZ significantly increased the relative mRNA expression and protein phosphorylation of PI3K and Akt, respectively. CONCLUSIONS: This study showed that intramuscular injection of CKZ has a significant therapeutic effect in SR FSGS rats, which may be associated with the activation of PI3K-Akt signaling by CKZ.