Renoprotective activity of Ribes diacanthum pall (RDP) against inflammation in cisplatin-stimulated mice model and human renal tubular epithelial cells

Ethnopharmacological relevance: Ribes diacanthum Pall (RDP) is mostly distributed in Mongolia. As a Mongolian folk medicinal plant, it is traditionally used to treat kidney diseases by the native inhabitants of Mongolia due to its effect of increasing urine output and eliminating edema. However, its renal protection mechanism remains to be elucidated.

Aim of the study: To assess the pharmacological mechanism of RDP from an anti-inflammatory point of view using cisplatin (CDDP)-induced kidney injury models in vivo and in vitro. The influence of RDP on the chemotherapy efficacy of CDDP was also evaluated in vitro.

Materials and methods: We established a CDDP-induced nephrotoxicity mouse model and a Human Renal Tubular Epithelial (HK-2) damage cellular model, respectively. In vivo, kidney function, the content of urine albumin, and renal histopathology examination were performed to observe the kidney injury. Moreover, the expression and secretion of inflammatory cytokines and adhesive molecules were examined by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and Real-Time PCR. The key protein levels of mitogen-activated protein kinase/nuclear factor kappa B (MAPK/NF-κB) signaling pathway were measured by western blotting analysis. Electrophoretic mobility shift assay (EMSA) was carried out to detect the activation of NF-κB. In vitro, inflammatory mediators and the proteins related to the NF-κB signaling pathway in HK-2 cells were measured by western blotting analysis. Besides, A549 cell lines were treated with CDDP and RDP to explore RDP's impact on CDDP chemotherapy.

Results: Gavage RDP decreased the elevated levels of serum creatinine (Scr), urea nitrogen (BUN), as well as the ratio of urine albumin and creatinine, ameliorated pathological changes of kidney tissue. Correspondingly, the RDP administration group showed a higher survival rate than that of the CDDP exposed group. The expression levels of a plethora of inflammatory mediators were inhibited by RDP treatment compared with the CDDP-exposed group. Furthermore, protein expression levels of MAPK/NF-κB signaling pathway significantly decreased after RDP intervention. For in vitro studies, we confirmed the inhibitory effect of RDP on relative protein expressions involving in the NF-κB pathway. The results also showed that RDP had no impairment on the inhibitory effect of CDDP on A549 cells.

Conclusion: These findings demonstrated RDP's anti-inflammatory effect against CDDP nephrotoxicity through in vivo and in vitro experiments, and suggested that RDP may have a potential application as an adjuvant medication for CDDP chemotherapy and other inflammatory kidney diseases.