Cordyceps sinensis attenuates renal fibrosis and suppresses BAG3 induction in obstructed rat kidney

Abstract

BAG3 regulates a number of cellular processes, including cell proliferation, apoptosis, adhesion and migration, and epithelial-mesenchymal transition (EMT). However, the role of BAG3 in renal tubular EMT and renal interstitial fibrosis remains elusive. This study aimed to examine the dynamic expression of BAG3 during renal fibrosis, and to investigate the efficacy of Cordyceps sinensis (C. sinensis) on renal fibrosis. A rat model of unilateral ureteral obstruction (UUO) was established, and the expression of BAG3 and α-SMA, and the efficacy of C. sinensis on renal fibrosis induced by UUO were examined. The results showed that UUO led to collagen accumulation, which was significantly suppressed by C. sinensis. UUO increased the expression of BAG3 and α-SMA, a mesenchymal marker, while UUO induced BAG3 and α-SMA expression was significantly inhibited by C. sinensis. In addition, immunohistochemical staining demonstrated that BAG3 immunoreactivity was restricted to tubular epithelium. In conclusion, BAG3 is a potential target for the prevention and/or treatment of renal fibrosis, and C. Sinensis is a promising agent for renal fibrosis.

Keywords: BAG3; Cordyceps sinensis; renal fibrosis; unilateral ureteral obstruction.

Figure 1

C. sinensis had nephroprotective effects in UUO rats. A. Representative images of HE staining of the kidney of rats on days 7, 14, and 21 after the sham, UUO operation, or UUO operation treated with C. sinensis. Scale bar: 100 μm. B. Representative images of Masson staining of the kidney of rats on days 7, 14, and 21 after the sham, UUO operation, or UUO operation treated with C. sinensis. Scale bar: 100 μm. C. The percentage of renal interstitial fibrosis in the kidneys (n = 10). D. The quantitative data of hydroxyproline content in the kidneys (n = 10). *, p < 0.05.

Figure 2

C. sinensis decreased α-SMA expression in UUO kidneys. A. Real-time RT-PCR analysis of α-SMA mRNA levels in Sham and UUO groups (n = 10). B. Western blot analysis of α-SMA protein levels in Sham and UUO groups. Representative images were presented. C. Densitometry analysis of α-SMA protein levels in Sham and UUO groups. D. Real-time RT-PCR analysis of α-SMA mRNA levels in UUO and UUO/C. sinensis groups (n = 10). E. Western blot analysis of α-SMA levels in UUO and UUO/C. sinensis groups. Representative images were presented. F. Densitometry analysis of α-SMA protein levels in UUO and UUO/C. sinensis groups (n = 10). α-SMA mRNA level was normalized to 18S rRNA. GAPDH was loading control for Western blot analysis. *p < 0.05.

Figure 3

BAG3 expression was increased in the UUO rat and suppressed by C. sinensis. A. Real-time RT-PCR analysis of BAG3 mRNA levels in Sham and UUO groups (n = 10). B. Western blot analysis of BAG3 protein levels in Sham and UUO groups. Representative images were presented. C. Densitometry analysis of BAG3 protein levels in Sham and UUO groups. D. Real-time RT-PCR analysis of BAG3 mRNA levels in UUO and UUO/C. sinensis groups (n = 10). E. Western blot analysis of BAG3 protein levels in UUO and UUO/C. sinensis groups. Representative images were presented. F. Densitometry analysis of BAG3 protein levels in UUO and UUO/C. sinensis groups (n = 10). BAG3 mRNA level was normalized to 18S rRNA. GAPDH was loading control for Western blot analysis. *p < 0.05.

Figure 4

Immunohistochemical staining of BAG3 and α-SMA in rat kidneys. A. Representative images of BAG staining in the kidney of rats on days 7, 14, and 21 after the sham, UUO operation, or UUO operation treated with C. sinensis. B. Representative images of α-SMA staining in the kidney of rats on days 7, 14, and 21 after the sham, UUO operation, or UUO operation treated with C. sinensis. Scale bar: 20 μm.