Emodin protects rat liver from CCl4-induced fibrogenesis via inhibition of hepatic stellate cells activation

Figure 1 Emodin protects the liver from CCl₄-induced fibrogenesis in rats via inhibition of hepatic stellate cell activation. A piece of liver tissue from each treated rat (n = 6 per group) was fixed with formalin, and then it was embedded in paraffin. A: Thin sections were cut and stained with HE; B: α-SMA proteins were stained by immunohistochemistry in liver tissue. Representative views from each group (n = 6 per group) are presented (original magnification, × 400). Arrows indicated an area positively labeled with α-SMA; C: Semi-quantification of α-SMA staining. Values are expressed as mean ± SD, n = 6 per group. ^aP < 0.05 vs CCl₄ group. Total RNA extracted from rat liver tissues was used to synthesize cDNA; D: The α-SMA mRNA was detected by real-time PCR, and mRNA levels are expressed as -fold differences relative to normal rat after normalization to the housekeeping gene’s GAPDH mRNA. Values are expressed as mean ± SD, n = 5 per group. ^aP < 0.05 vs CCl₄ group.

Figure 2 Emodin decreases the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. Serum samples were obtained from each treated rat through heart puncture when sacrificed. After coagulation, serum AST and ALT activities were determined by routine laboratory methods. Values are expressed as mean ± SD, n = 6 per group. AST: ^aP < 0.05 vs CCl₄ group; ALT: ^cP < 0.05 vs CCl₄ group.

Figure 3 Emodin decreases the levels of serum transforming growth factor-β1 (TGF-β1) and mRNA levels in liver tissues in the rat model. Serum and liver tissue were obtained from each treated rat. A: Levels of serum TGF-β1 were determined by ELISA; B: Total RNA extracted from rat liver tissues was used to synthesize cDNA. The mRNA level of TGF-β1 in liver tissues was detected by real-time PCR, and mRNA levels were expressed as -fold differences relative to normal rat after normalization to the housekeeping gene’s GAPDH mRNA. Values are expressed as mean ± SD, n = 5 per group. ^aP < 0.05 vs CCl₄ group.

Figure 4 Emodin inhibits expression of protein and mRNA levels of Smad4 in liver tissues in the rat model. A piece of liver tissue was collected from each treated rat. A: Smad4 proteins in liver tissue were stained by IHC. Representative views from each group (n = 6 per group) are presented (original magnification, × 400). Arrows indicate an area positively labeled with Smad4; B: Semi-quantification of Smad4 staining. Values are expressed as mean ± SD, n = 6 per group. ^aP < 0.05 vs CCl₄ group; C: Real-time PCR analyses of the mRNA levels of Smad4. Values are presented as means ± SD, n = 5 per group. GAPDH was used as an invariant internal control for calculating mRNA -fold changes; D, E: Western blotting analyses of the protein abundance of Smad4. GAPDH was used as an invariant control for equal loading. ^aP < 0.05 vs CCl₄ group.