双嘧达莫对胃癌多药耐药的逆转实验研究

目的 研究双嘧达莫对胃癌细胞多药耐药的逆转作用。方法 逐渐递增长春新碱浓度诱导胃癌细胞株SGC790 1产生多药耐药性 (SGC790 1r)。以双嘧达莫为逆转剂 ,MTT法测定抗癌药对肿瘤细胞的杀伤作用 ;激光全聚焦显微镜测定肿瘤细胞内柔红霉素和钙离子荧光强度。结果 胃癌SGC790 1r细胞对长春新碱、柔红霉素、丝裂霉素及顺铂的耐药性分别为SGC790 1细胞的 4.46倍、14.95倍、2 1.2 0倍和 16 .0 6倍。经双嘧达莫(5 0 μg/ml)预处理 1h后 ,柔红霉素对SGC790 1r的半数抑制浓度明显下降 (P <0 .0 5 )。SGC790 1r在静息时细胞内Ca2 + 明显高于药物敏感的母细胞株SGC790 1;细胞内柔红霉素的荧光强度亦明显降低 (P <0 .0 5 )。双嘧达莫 (5 0 μg/ml)使SGC790 1r细胞内Ca2 + 明显下降 ,柔红霉素荧光强度显著提高 (P <0 .0 5 ) ;对药物敏感细胞SGC790 1无明显作用。结论 双嘧达莫增加柔红霉素在耐药细胞内的积累 ,部分逆转SGC790 1r的耐药性。

Prevalence of porcine endogenous retrovirus in Chinese pig breeds and in patients treated with a porcine liver cell-based bioreactor

AIM： To determine the prevalence of porcine endogenous retrovirus （PERV） in various pig breeds raised in China including Chinese experimental mini-pigs by PERV-reverse transcriptase （PERV-RT enzyme）. Moreover, the potential for infection of PERV was investigated in patients treated with a bioreactor based on porcine liver cells （n = 3）. METHODS： Pig serum, liver and muscle cell-free supernatants were collected from various Chinese pig breeds. Porcine hepatocytes were isolated with a two-step perfusion method. Three patients with acute or chronic liver failure were treated with a bioartificial liver support system （BALSS） for 8-12 h and serum samples were collected from the patients before, immediately after and 30 d after treatment. RESULTS： The activities of PERV-RT enzyme in pig liver and muscle cell-free supernatants were higher than in normal human controls. PERV-TR enzyme activity did not increase in patients before and after 1 mo of treatment. PERV-RT activities were not significantly different when compared with pre-treatment group （1.544±0.155576）, the post-treatment groups （1.501±0.053507, 1.461±0.033808 and 1.6006667±0.01963 for 0, 14 and 30 d post-treatment, respectively, P〉0.05）, and normal control group （1.440±1.0641, P〉0.05）. RT enzyme activity in Chinese experimental mini-pigs was higher than in normal human control group （1.440±1.0641 U/mL, P〈0.05）, and not significantly different （P〉0.05） when compared with the pig breeds except in the muscle supernatants. All the samples including muscle and liver cell supernatants from the Chinese mini-experimental pigs and the four domestic Chinese pig breeds contained PERVs. CONCLUSION： These results suggest that the risk of PERV infection through BALSS containing porcine liver cells without immunosuppressants may be quite low. Although there were PERVs in Chinese experimental mini-pigs and porcine liver cell culture suspensions, we did not find any evidence of persistent PERV infection in patients treated with this porcine hepatocyte-based bioartificial liver.

Inhibitory effect of acetylshikonin on human gastric carcinoma cell line SGC-7901 in vitro and in vivo

AIM:To investigate the inhibitory effect of acetylshikonin on human gastric carcinoma cell line SGC-7901 and its mechanism. METHODS:MTT assay was used to assess the inhibitory effect of acetylshikonin on proliferation of SGC-7901 cells.Apopt osis-inducing effect was determined by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling with Hoechst staining.Expression of mRNA and protein in Bcl-2 and Bax was analyzed by reverse transcription-polymerase chain reaction and Western blot.Antitumor effect of acetylshikonin on a mouse SGC-7901 model was also determined. RESULTS:Forty-eight hours after treatment with acetylshikonin,MTT assay showed that acetylshikonin inhibited the proliferation of SGC-7901 cells in a dose-dependent manner.The half maximal inhibitory concentration of acetylshikonin to SGC-7901 cells was 0.428±0.07 mg/L.Cell shrinkage,nuclear pyknosis and chromatin condensation,which are the characteristics of cell apoptosis,were observed in treated SGC-7901 cells and the percentage of apoptosis increased in a dose-dependent manner.Acetylshikonin downregulated the expression of Bcl-2 and up-regulated the expression of Bax in the treated SGC-7901 cells compared with the controls.The experiment in vivo showed that 0.5,1,and 2 mg/kg of acetylshikonin significantly inhibited the growth of tumor in the mouse SGC-7901 model,with an inhibitory rate of 25.00%-55.76%. CONCLUSION:Acetylshikonin inhibits the growth of SGC-7901 cells in vitro and in vivo by inducing cell apoptosis.

Emodin promoted pancreatic claudin-5 and occludin expression in experimental acute pancreatitis rats

AIM:To investigate the effect of emodin on pancreatic claudin-5 and occludin expression,and pancreatic paracellular permeability in acute pancreatitis(AP).METHODS:Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct.Emodin was injected via the external jugular vein 0 or 6 h after induction of AP.Rats from sham operation and AP groups were injected with normal saline at the same time.Samples of pancreas were obtained 6 or 12 h after drug administration.Pancreatic morphology was examined with hematoxylin and eosin staining.Pancreatic edema was estimated by measuring tissue water content.Tumor necrosis factor(TNF)-α and interleukin(IL)-6 level were measured by enzyme-linked immunosorbent assay.Pancreatic paracellular permeability was assessed by tissue dye extravasation.Expression of pancreatic claudin-5 and occludin was examined by immunohistology,quantitative real-time reverse transcriptase polymerase chain reaction and western blotting.RESULTS:Pancreatic TNF-α and IL-6 levels,wet/dry ratio,dye extravasation,and histological score were significantly elevated at 3,6 and 12 h following sodium taurocholate infusion;treatment with emodin prevented these changes at all time points.Immunostaining of claudin-5 and occludin was detected in rat pancreas,which was distributed in pancreatic acinar cells,ductal cells and vascular endothelial cells,respectively.Sodium taurocholate infusion significantly decreased pancreatic claudin-5 and occludin mRNA and protein levels at 3,6 and 12 h,and that could be promoted by intravenous administration of emodin at all time points.CONCLUSION:These results demonstrate that emodin could promote pancreatic claudin-5 and occludin expression,and reduce pancreatic paracellular permeability.

Panax notoginseng saponins ameliorates experimental hepatic fibrosis and hepatic stellate cell proliferation by inhibiting the Jak2/Stat3 pathways

OBJECTIVE： To investigate the inhibitory effect of Panax notoginseng saponins（PNS） on liver fibrosis and explore the underlying mechanisms.METHODS： Carbon tetrachloride（CCl4）-treated rats and hepatic stellate cells（HSCs） were used. The effect of PNS on CCl4-induced liver fibrosis was studied with histochemical and biochemical analysis.Transforming growth factor（TGF）-β1, α-smooth muscle actin（α-SMA）, and collagen Ι m RNA expression were determined by reverse transcriptase-polymerase chain reaction（RT-PCR）. Mean-while, the protein expression levels of α-SMA, collagen Ι, phosphorylation-Janus activated kinase signal transducer（p-Jak2） / Jak2, and phosphorylation-activator of transcription（p-Stat）3 / Stat3 were determined by immunohistochemistry and / or immunoblotting.RESULTS： PNS treatment significantly improved the liver function of rats as indicated by decreased serum enzymatic activities of alanine aminotransferase and aspartate aminotransferase. Histopathological results indicated that PNS alleviated liver damage and reduced the formation of fibrous septa. Moreover, PNS significantly decreased liver hydroxyproline and significantly attenuated expressions of collagen p-Stat3 / StatⅠ, α-SMA, TGF-β1, p-Jak2 / Jak2,and 3 in the rat liver fibrosis model and HSCs.CONCLUSION： PNS can relieve liver fibrosis by modulating Jak2/Stat3 signaling transduction pathway, which may be one of its mechanisms to suppress hepatic fibrosis.