肝纤维化的逆转策略及研究现状

Effects of plumbagin on apoptosis and expression of apoptosis-related proteins in human hepatic stellate cells

AIM: To investigate the effects of plumbagin on leptin-induced apoptosis and expression of apoptosis-related protein in human hepatic satellite cells (HSC-LX2) and to explore the anti-fibrotic mechanism of plumbagin.

METHODS: After HSC-LX2 cells were cultured in vitro, stimulated with leptin for 24 h, and treated with different concentrations of plumbagin for 24 h, cell apoptosis was detected by flow cytometry; cell ultrastructure was observed by transmission electron microscopy; and the protein expression of P53, Bax, and Bcl-2 was determined by immunocytochemistry.

RESULTS: HSC-LX2 cells were divided into 6 groups: untreated cells (blank control group), those treated with 100 μg/L leptin (leptin control group), those treated with both leptin and colchicin (colchicin group), those treated with both leptin and 2, 8 or 16 μmol/L plumbagin (2, 8, 16 μmol/L plumbagin group). The apoptosis rate of HSC-LX2 cells was significantly increased in plumbagin groups. The apoptosis rates of cells treated with 8 or 16 µmol/L plumbagin or colchicine were significantly higher than those of the blank control group and leptin group (5.21% ± 0.41%, 8.10% ± 0.63%, 10.1% ± 1.08% vs 1.40% ± 0.13%, 2.85% ± 0.21%, all P < 0.01). Transmission electron microscopy revealed varying degrees of apoptosis in the leptin group or plumbagin groups. Immunocytochemistry analysis showed that the protein expression levels of P53 and Bax were higher and that of Bcl-2 was lower in plumbagin groups than in the leptin group (Bax: 85.24 ± 1.08, 86.35 ± 1.12, 91.13 ± 1.13 vs 56.63 ± 0.94; P53: 25.32 ± 0.6, 38.14 ± 0.71, 41.19 ± 0.72 vs 19.25 ± 0.46; Bcl-2: 32.12 ± 0.43, 27.71 ± 0.38, 21.46 ± 0.46 vs 44.51 ± 0.56, all P < 0.05 or 0.01).

CONCLUSION: Plumbagin can significantly accelerate leptin-induced apoptosis of HSC-LX2 cells possibly by up-regulating P53 and Bax expression and down-regulating Bcl-2 expression.

Quantitative evaluation of carotid elasticity in cirrhotic patients by echo-tracking technique

AIM: To quantitatively detect the carotid elasticity in patients with liver cirrhosis by echo-tracking (ET) technique.

METHODS: ET technique was used to determine the stiffness parameter (b), pressure-strain elasticity modulus (Ep), arterial compliance (AC), argumentation index (AI) and one-point pulse wave velocity (PWVb) of carotid in 20 cirrhotic patients and 150 normal adults.

RESULTS: The values of b and AI in patients with liver cirrhosis were higher than those in normal adults (P = 0.02; P = 0.00), while of the values of Ep, AC and PWVb were not markedly different between cirrhotic patients and normal adults (P > 0.05).

CONCLUSION: The carotid elasticity in cirrhotic patients is decreased, and it can be detected quantitatively by ET technique.

Construction and identification of rat pcDNA3.1(+)-antisense TβRI eukaryotic expressing plasmid

AIM: To construct rat pcDNA3.1(+)-antisense TβRI (transforming growth factor beta receptor I) eukaryotic expressing plasmid, and to provide the experimental foundation for intervening the pathogenesis and development of liver fibrosis through TβRI.

METHODS: TRIzol assay was performed to obtain the total RNA from the rat liver tissues. The integrality, concentration and purity of total RNA were detected by ultraviolet spectrophotometry and agarose electrophoresis. The fragment of TβRI cDNA was obtained by reverse transcription polymerase chain reaction (RT-PCR), and then amplified by nest PCR. CaCl2 method was used to induce the susceptibility of cells. The eukaryotic expressing vector, at its multiple cloning sites, as well as the fragment of TβRI, was digested by EcoRⅠand Xhol, and then, was purified and retrieved by agarose electrophoresis separation. pcDNA3.1(+)-antisense TβRI eukaryotic expressing plasmid was constructed by a directional inverted joins with the purified linear pcDNA3.1(+) and the purified fragment of TβRI. This recombinant plasmid was transfected into E.coli JM109 by means of heat shock. The recombinant was identified by restriction endonuclease digestion and DNA sequence analysis.

RESULTS: Agarose electrophoresis showed that the strips of 18S and 28S were integral. Furthermore, the luminosity of the 28S strip was twice as high as 18S strip. So the total RNA was considered to be in integrity. The ratio of A₂₆₀/A₂₈₀ was 1.915 0, and the total RNA was considered to be in good purity. The concentration of total RNA was 770 mg/L. The two fragments digested from pcDNA3.1(+)-antisense TβRI by EcoRⅠand XholⅠrepresented 5.3 kb and 432 bp after agarose electrophoresis, indicating the successful construction of pcDNA3.1(+)-antisense TβRI. Sequence analysis showed the same sequence as expected.

CONCLUSION: The pcDNA3.1(+)-antisense TβRI eukaryotic expressing plasmid is constructed successfully.

Antisense oligonucleotides-based inhibition of gene and protein expression of tissue inhibitor of metalloproteinase-2 on experimental liver fibrosis in rats

AIM: To investigate the inhibitory effect of tissue inhibitor of metalloproteinase-2 (TIMP-2) targeted antisense oligonucleotide (asON) on the progress of experimental liver fibrosis in rats.

METHODS: Twenty-two rats were divided into asON treatment (n = 6), model (n = 6), and normal control group (n = 10). The liver fibrosis model was induced by human serum albumin (HSA). During modeling, the rats were treated with antisense oligonucleotides via tail vein. The level of TIMP-2 expression was detected by reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization, immunohistochemical staining and enzyme linked immunosorbent assay (ELISA). The effect of asON on liver fibrosis was analyzed by histopathological exami-nation, immunohistochemical staining of collagenⅠand Ⅳ, and special staining of collagen fiber as well as electron microscopy.

RESULTS: The pathological grading was notably im-proved in asON group than that in model group (u = 2.071, P <0.05). The serum and tissue expression of TIMP-2 were lower in asON group than those in model group (T = 55, P <0.05; t = 3.332, P <0.05), but higher than those in the control (T = 55, P <0.05; t = 5.550, P <0.05). Image quantitative analysis for immunohistochemical staining of collagen Ⅳ showed that the value was significant decreased in asON group as compared with that in model group (t = 2.310, P <0.05), but still higher than that in the control (t = 3.623, P <0.05); The value for collagenⅠwas also decreased in asON group as compared with that in model group (t = 2.845, P <0.05). Less collagen deposition was found in the hepatic sinusoid of asON group, which was not significantly different from that of model group.

CONCLUSION: TIMP-2 targeted asON can inhibit the progress of experimental liver fibrosis in rats.