RESUMO
Objective: To establish a convenient non-invasive tracheal perfusion method for constructing a mouse model of silicosis-induced pulmonary fibrosis. Methods: The specific pathogen-free C57BL/6 mice were randomly divided into control group and model group, with 15 mice in each group. After anesthesia, a 22G arteriovenous indwelling needle was used to inset into the trachea through the mice's mouth. The model group mice were perfused with 0.1 mL of silica suspension with a mass concentration of 25 g/L, and the mice in the control group were perfused with an equal volume of 0.9% sodium chloride solution. On the 7th, 14th, and 30th day after modeling, the body weight of the mice was measured, and the lung tissue morphology and pathological changes were observed. The expression of α-smooth muscle actin (α-SMA) and collagen type 1 alpha 1 (COL1A1) protein in lung tissue of mice was detected by immunofluorescence on the 30th day after modeling. Results: There was no death of mice in the two groups during the experiment. There was no significant difference in body weight between the two groups (P>0.05). The lung tissues of the mice in the model group were pinkish-gray and uneven in color on the 7th and 14th days after dust exposure. On the 30th day after dust exposure, the lung tissue of the mice in the model group was gray and hard, and unevenly distributed silicon nodules were visible by the naked eyes. The histopathology results of lung tissue showed that compared with the mice in control group, the model group mice exhibited persistent aggravation of pulmonary inflammation, thickening of alveolar septum, infiltration of inflammatory cells gradually clustering into clumps, and an increasing number of fibrous foci.On the 30th day after dust exposure, the relative expression of α-SMA and COL1A1 proteins in the lung of the model group was higher than those in the control group (median： 72.59 vs 5.91, 35.62 vs 10.07, both P<0.05). Conclusion: The method of tracheal perfusion silica suspension of mice using 22G arteriovenous indwelling needle can successfully construct an animal model of silicosis fibrosis. This method is convenient, safe and effective, and is worth promoting.
RESUMO
Objective To investigate the association between hepatitis B virus (HBV)genotype, the mutations in HBV basic core gene promoter(BCP), pre C/C gene region and treatment response to interferon (IFN)α-1b. Methods Hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients were treated with IFNα-Ib for 6 months and were followed up for 6 months after the end of treatment. Restriction Fragment Length Polymorphism (RFLP) was used for determining HBV genotype. HBV DNA was amplified by polymerase chain reaction (PCR) and analyzed for BCP and pre C/C gene region by sequencing. Measurement data were compared using t test and analysis of variance. Enumeration data were compared using chi-square test, Fisher exact probability test.Logistic regression analysis was utilized for multi-factor analysis. Results There were 39 patients who completed the treatment and follow up in this study. At the end of treatment, 16(41.0%) patients showed response to the IFNα-lb treatment. At the end of follow-up, four out of 16 patients who achieved on treatment response relapsed. Among 3a patients, 29 (74.4 %) were infected with genotype B and 10 (25. 6%) with genotype C. The treatment response rates were not significant different between the groups with different genotypes. The double mutation pattern (T1762/A1764) was found in eight (20. 5%) patients. The response rates to IFNα-lb treatment were not significant different between the group with and without double mutation pattern. A1896 mutation was detected in eight patients at baseline. Three of them became HBeAg negative at the end of treatment and returned to HBeAg positive during follow-up. The non-lyphocyte epitope mutations, L60V and I97L, were found in 15 patients (38. 5%) and 14 patients (35.9%), respectively. At the end of follow-up, the patients with 60V had a significantly lower HBeAg seroconversion rate and HBV DNA undetectable rate compared to the patients with 60L (Fisher exact probability test; P = 0.0126 and 0.0069,respectively). The HBV DNA undetectable rates in the patients with 97I were significantly lower than those in patients with 97L both at the end of treatment and the end of follow-up (Fisher exact probability test; P= 0.0484 and 0. 0024, respectively). Logistic regression analysis results showed that there was no association between the above viral mutations and the treatment response to IFNαlb. Conclusions There is no association between HBV genotype, BCP double mutation pattern and IFN-α treatment response. The non-lyphocyte epitope mutations, L60V and I97L, may have impact on IFN-α treatment response.