肝星状细胞的可塑性及其对肝纤维化的意义

Effect of fluid shear stress on activation of hepatic stellate cells and expression of α-SMA, collogen-Ⅰ, collogen-Ⅲ, MMP-2, and MMP-9

AIM: To investigate the effects of different types of fluid shear stress on the activation of hepatic stellate cells-T6 (HSC-T6) and expression of α-SMA, collogen-Ⅰ, collogen-Ⅲ, MMP-2, and MMP-9.

METHODS: HSC-T6 cells were seeded on slides precoated with rat tail collagen and exposed to different types of fluid shear stress (6, 12, 20 dyn/cm²) for 3 h, and static cells served as controls. The gene expression of α-SMA, collogen-Ⅰ, collogen-Ⅲ, MMP-2 and MMP-9 was assayed by real-time RT-PCR. Intracellular α-SMA protein was analyzed by FACS.

RESULTS: After treatment by fluid shear stress, the expression of α-SMA and collogen-Ⅲ was lower in the low shear stress (6 dyn/cm²) group than that in the control group. However, the expression of α-SMA was higher in the moderate (12 dyn/cm²) and high (20 dyn/cm²) shear stress groups than that in the control group, and the expression of collogen-Ⅲ was higher in the high shear stress group than that in the control group. There was no significant difference in the expression of collogen-Ⅰ among different fluid shear stress groups. The expression of MMP-2 was higher that in three fluid shear stress groups than in the control group.

CONCLUSION: High fluid shear stress can lead to the activation of HSC-T6 cells and promote the mRNA expression of α-SMA, collogen-Ⅲ and MMP-2.

Effect of sargassum fusiforme polysaccharides on lipopolysaccharide-induced proliferation, activation, oxidative damage and apoptosis of rat hepatic stellate cells

AIM: To investigate the effect of sargassum fusiforme polysaccharides (SFPS) on the proliferation, activation, oxidative damage and apoptosis of lipopolysccharide (LPS)-induced rat hepatic stellate cells (HSCs), and to evaluate the anti-fibrotic mechanism of SFPS.

METHODS: Cultured rat HSCs were divided into five groups: control group, LPS group, and three LPS plus SFPS groups (treated with LPS plus low-, medium- or high-dose SFPS). After 48 h, cell proliferation was assessed by MTT colorimetric assay. Apoptotic cells were detected by annexin V-FITC/PI double labeling and flow cytometry. MDA/SOD contents were measured by colorimetry. The levels of type I collagen were measured by ELISA. Western blot were used to detect the expression of α-smooth muscle actin.

RESULTS: LPS induced proliferation, increased the secretion of MDA and the expression of typeⅠcollagen and α-smooth muscle actin, and reduced the secretion of SOD in HSCs (all P < 0.05). Compared to the LPS group, treatment with different doses of SFPS inhibited proliferation, induced apoptosis, reduced secretion of MDA, decreased the expression of typeⅠcollagen and α-SMA, and increased secretion of SOD (all P < 0.05).

CONCLUSION: These results suggest that SFPS can alleviate liver fibrosis by inducing apoptosis of HSCs and protecting against LPS-induced oxidative stress.