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Purpose To clarify the effect of adenosine on brain metastasis of lung cancer and the possible mechanism of adenosine promoting brain metastasis of lung cancer. Methods Western blot was used to dynamically detect the expression level of hypoxia inducible factor-1 (HIF-1) in lung cancer cells and tight junction protein ZO-1 in brain microvascular endothelial cells on blood-brain barrier. The content of adenosine in lung cancer cell culture was determined by ELISA. Fluorescence analysis was used to detect the changes of permeability of the blood-brain barrier model in vitro. Hemocytometer counts the number of A549 lung cancer cells in Transwell's lower chamber. Results The expression level of HIF-1 in lung cancer cells and the content of adenosine in lung cancer cell culture reached the highest level when lung cancer cells were deprived of oxygen for 12 hours. At the same time, the expression level of ZO-1 protein in the blood-brain barrier was the lowest, the blood-brain barrier permeability was the highest (7.11), and the number of lung cancer cells passing through the blood-brain barrier model was the highest (84.6). The permeability of the blood-brain barrier model increased after the action of adenosine, and its change trend was consistent with the effect of hypoxic lung cancer cell culture solution. Conclusion Hypoxia can induce the lung cancer cell to release adenosine, the increased adenosine can reduce the expression of tight junction protein ZO-1 in blood brain barrier, which leads to the increase of permeability of blood-brain barrier and eventually lead to brain metastasis of lung cancer.
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Objective To investigate the impact of tumor necrosis factor-α (TNF-α) on intestinal mucosa permeability and the protective effect of probiotics in mice with acute liver failure (ALF).Methods Thirty male BALB/c mice aged 6-8 weeks were randomly divided into normal control,ALF and intervention groups (10 for each group).Mice in intervention group were fed with live combined bifidobacterium and lactobacillus (900 mg · kg-1 · d-1) by gavage,while those in normal control and ALF groups were fed with normal saline (9 mL · kg-1 · d-1).After two weeks,mice in ALF and intervention groups were given an intraperitoneal injection of D-galactosamine (3.0 g/kg) to induce liver failure,and all mice were sacrificed 9 h after the injection.Biochemical markers were tested,expressions of TNF-α mRNA in liver tissues and zonula occluden-1 (ZO-1) mRNA in ileum tissues were detected by real-time PCR,and the expression of ZO-1 protein in ileum tissues was detected by Western blotting.One-way analysis of variance or Kraskal-Wallis test was performed to explore the differences in biochemical markers,TNF-α mRNA,ZO-1 mRNA and ZO-1 protein expressions among groups,and Pearson test was used to analyze the correlations between the expression of ZO-1 protein in ileum tissues and serum level of TNF-α or plasma levels of endotoxins.Results Serum alanine aminotransferase (ALT),aspartate aminotransferase (AST),TNF-α and plasma level of endotoxins in ALF group were significantly higher than those in normal control group (P ＜0.01) ; while compared with ALF group,the above biomarkers were significantly decreased in the intervention group (P ＜ 0.01).The expression of TNF-α mRNA in liver tissues in ALF group was higher than that in the normal control group (Z =4.038,P ＜ 0.01) ; while compared with ALF group,it was decreased in intervention group (Z =3.780,P ＜ 0.01).The expressions of ZO-1 mRNA and ZO-1 protein in ileum tissues in ALF group were lower than those in normal control group (P ＜ 0.01) ; while compared with ALF group,those in intervention group were increased (P ＜ 0.01).Pearson analysis showed that the expression of ZO-1 protein in ileum tissues was negatively correlated with serum level of TNF-α level and plasma level of endotoxin (r =-0.946 and-0.919,both P ＜ 0.01).Conclusions TNF-α may be involved in the increased permeability of intestinal mucosa in mice with ALF.Live combined bifidobacterium and lactobacillus may relieve liver damages through inhibiting endotoxin synthesis and release,and ameliorate the permeability of intestinal mucosa through up-regulating ZO-1 protein expression.
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Objective To investigate the protective effects of astragaloside Ⅳ on blood-brain barrier(BBB) and influence on expression of ZO-1 protein after cerebral ischemia and reperfusion in rats.Methods 72 SD rats were randomly divided into:sham operation group,model group and two astragaloside Ⅳ therapy groups [group A(10 mg/kg,group B(20 mg/kg)].Method of Evans blue leakage and water content in the brain tissue were used to investigate the permeability of the BBB,and method of immunohistochemistry combined with image analysis was used to measure the expression of ZO-1 protein in microvessels.Results Compared with those in the model group,Evans blue leakage and water content were less and the number of ZO-1 possitive vessels was increased in the two astragaloside Ⅳ therapy groups.There were statistical differences between therapy groups and model group(all P