Pseudoginsengenin DQ Exhibits Therapeutic Effects in Cisplatin-Induced Acute Kidney Injury via Sirt1/NF-κB and Caspase Signaling Pathway without Compromising Its Antitumor Activity in Mice

Abstract

In this study, the protective effects of pseudoginsengenin DQ (PDQ) on cisplatin (CDDP)-induced nephrotoxicity were assessed, with a primary investigation into the mechanisms involved. Our results showed that pretreatment with PDQ remarkably restored levels of blood urea nitrogen (BUN) and creatinine (CRE), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Meanwhile, PDQ decreased the CDDP-induced overexpression of heme oxygenase 1 (HO-1), cytochrome P450 E1 (CYP2E1), TNF-α, nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in renal tissues. Hoechst 33258 and TdT-mediated dUTP nick-end labeling (TUNEL) staining showed that CDDP-induced renal tubular cell apoptosis was apparently inhibited by PDQ. Western blotting showed that PDQ reversed the CDDP-induced (1) downregulation of Sirtuin-1 (Sirt-1), nuclear-related factor 2 (Nrf2), and Bcl-2, and (2) upregulation of NF-κB, Nox-4, Bax, caspase-9, and caspase-3. In addition, PDQ enhanced the antitumor activity of cisplatin in Lewis lung cancer xenograft tumor model mice. In conclusion, we found that PDQ exerted a renal protective effect against CDDP-induced acute nephrotoxicity via Sirt1/NF-κB and the caspase signaling pathway without compromising the antitumor activity of CDDP, which provides a new potential strategy for the clinical treatment of cancer and presents a new medicinal application of PDQ.

Keywords: CDDP-induced acute kidney injury; Sirt1/NF-κB; caspase; pseudoginsengenin DQ.

Figure 1

Experiment design (A); morphological change in kidney tissues (B); effects of PDQ on the levels of blood urea nitrogen (BUN) (C) and creatinine (CRE) (D). n = 8, ** p < 0.01 vs. normal group; ## p < 0.01 vs. cisplatin group.

Figure 2

Histological examination of morphological changes in kidney tissues. Renal tissues were stained with hematoxylin and eosin (H&E) (100×, 400×), and the necrocytosis grade was assessed by ridit analysis. n = 8, ** p < 0.01 vs. normal group; # p < 0.05, ## p < 0.01 vs. cisplatin group.

Figure 3

Histological examination of morphological changes in kidney tissues. Renal tissues stained with Hoechst 33258 (400×) (A) and TdT-mediated dUTP nick-end labeling (TUNEL) (400×) (B); renal tubular cell apoptosis and the presence of TUNEL-positive cells were measured by an image analyzer. n = 8, * p < 0.05 vs. normal group; # p < 0.05 vs. cisplatin group.

Figure 4

Effects of PDQ on the protein expression of Bax, Bcl-2, caspase-3, and caspase-9. n = 3, ** p < 0.01 vs. normal group; # p < 0.05, ## p < 0.01 vs. cisplatin group.

Figure 5

Effects of PDQ on the levels of glutathione (GSH) (A), malondialdehyde (MDA) (B), superoxide dismutase (SOD) (C), and catalase (CAT) (D) in cisplatin-induced acute kidney injury (AKI). All data are expressed as the mean ± S.D., n = 8. * p < 0.05 vs. control group; # p < 0.05 vs. cisplatin group.

Figure 6

Pretreatment with PDQ inhibited the cisplatin (CDDP)-induced increase of heme oxygenase 1 (HO-1) (green) (A) and cytochrome P450 E1 (CYP2E1) (green) (B) in renal tubular epithelial cells. The expression levels of HO-1 and CYP2E1 were assessed by immunofluorescence staining (magnification, 200×). n = 8, ** p < 0.01 vs. control group; # p < 0.05, ## p < 0.01 vs. cisplatin group. DAPI (blue) was used as a nuclear counterstain.

Figure 7

Effects of PDQ on the protein expression of Sirtuin-1 (Sirt-1), nuclear-related factor 2 (Nrf2), Nox-4, and nuclear factor-kappa B (NF-κB). n = 3, * p < 0.05, ** p < 0.01 vs. normal group; # p < 0.05, ## p < 0.01 vs. cisplatin group.

Figure 8

Effects of PDQ on the levels of inflammatory cytokines in cisplatin-induced nephrotoxicity. The levels of tumor necrosis factor-α (TNF-α) (A) and interleukin-1β (IL-1β) (B) in kidney tissues were determined by ELISA kits. All data are expressed as mean ± S.D., n = 8. * p < 0.05 vs. control group; # p < 0.05 vs. cisplatin group.

Figure 9

Effects of PDQ on the expression of inducible nitric oxide synthase (i-NOS), TNF-α, NF-κB, and cyclooxygenase-2 (COX-2); (400×). Protein expression was examined by immunohistochemistry; arrows show positive protein expression in renal tubular epithelial cells. n = 8, ** p < 0.01 vs. control group; ## p < 0.01 vs. cisplatin group.

Figure 10

Effects of PDQ on the antitumor activity of cisplatin against Lewis lung cancer xenograft tumors in C57BL/6 mice. n = 10, ## p < 0.01 vs. model control group.