Effects of silibinin on hepatic warm ischemia-reperfusion injury in the rat model

Abstract

Objectives: Liver ischemia-reperfusion injuries (I/RI) are typically the main causes of liver dysfunction after various types of liver surgery especially liver transplantation. Radical components are the major causes of such direct injuries. We aimed to determine the beneficial effects of silibinin, a potent radical scavenger on liver I/RI.

Materials and methods: Thirty-two rats were divided into 4 groups. Group I: VEHICLE, the rats underwent laparotomy and received DMSO, group II: SILI, laparotomy was done and silibinin was administered. Group III: I/R, the rats received DMSO and were subjected to a liver I/R procedure and group IV: I/R+SILI, the animals underwent the I/R procedure and received silibinin. After 1 hr of ischemia followed by 3 hr reperfusion, blood was collected to evaluate the serum marker of liver injuries. Hepatic tissue was harvested to investigate glycogen content, histological changes, and vasoregulatory gene expression.

Results: Results showed that serum AST, ALT, LDH, GGT, ALP, and hyaluronic acid (HA) increased significantly in I/R group compared with the VEHICLE group. Silibinin reduced this elevation except for GGT. Silibinin inhibited hepatocyte vacuolization and degeneration, endothelium damages, sinusoidal congestion and inflammation, and glycogen depletion during I/R. ET-1 mRNA was overproduced in the I/R group compared with the VEHICLE group which was decreased by silibinin. KLF2 and eNOS expression was reduced during I/R compared with the VEHICLE group. Silibinin elevated KLF2 expression but had no meaningful effect on eNOS expression.

Conclusion: Silibinin protected the liver from I/RI. Silibinin could improve liver circulation by preventing sinusoidal congestion, inflammation, and perhaps modification of the vasoregulatory gene expression.

Keywords: ET-1; KLF2; Liver Ischemia/reperfusion; Silibinin; eNOS.

Figure 1

Schematic diagram of the study design. I/R: ischemia-reperfusion. HA: hyaluronic acid

Figure 2

Vehicle group. Normal structure and radial alignment around the central vein (CV) (A); SILI group, health CV endothelium (B); I/R group, down and up arrows: cytoplasmic vacuolization. Right arrows: hydrotropic degeneration. Left arrow: sinusoidal congestion (C); I/R group. Up arrow: separation of sinusoidal endothelial cells and enlargement of CV. Right arrow: neutrophil infiltration around CV. Down arrow: dilated sinusoids. Left arrows: activated and marginated Kupffer cells (D); I/R+SILI group. Up arrow: mild degeneration, left arrow: minimal vacuolization, right arrows: less damaged CV endothelium, and down arrow: limited dilation (E); Vehicle group. Arrows: glycogen deposition in hepatocyte cytoplasm (F); SILI group. Homogenous distribution of glycogen (G); I/R group. The large area of glycogen depletion (H); I/R+SILI group. Less frequent glycogen depletion (I)

Figure 3

Relative KLF2, ET-1 and eNOS gene expression between the four studied groups. ** (P<0.01) and *** (P<0.001) compared to VEHICLE group. # (P<0.05) compared to I/R group. KLF2: Kruppel-like factor 2; ET-1: endothelin-1; eNOS: endothelial nitric oxide synthase