Study On The Effect Of Age On Telomerase Activity In Pulmonary Fibrosis Model In Mice

Objective: Through investigation and Research on the expression level of E-cadherin(E-cad), alpha Smooth Muscle Actin(SMA), Vimentin and Telecommunicator Emergency Response Taskforce(TERT) in the pulmonary fibrosis process of the elderly mice and young mice, comparison of the level of telomerase activity and degree of pulmonary fibrosis disease in different age mice, we study the effect of age on the degree of lung fibrosis and the changes of telomerase activity in the progress of lung fibrosis mice.Methods: 50 male C57BL/6 mice of 20 weeks old were randomly devided into two groups,25 selected as the youth group, the remaining 25 mice were fed to 25 weeks old and selected as the elderly group.Then the two groups were randomly divided into the control group(n=5),which was injected with 0.9% Sodium Chloride Injection for 28 days and four model groups(n=5),which was injected with bleomycin dilution(5mg/kg) in the trachea. Left lung specimens was collected after 28 days in the control group,while in model groups,left lung specimens were collected after 7,14, 21, 28 days. HE staining and Masson staining were used to observe whether the model of pulmonary fibrosis in mice was successful. Then the selected epithelial cell marker protein E-cadherin(E-cad),stromal cell marker protein alpha Smooth Muscle Actin(α-SMA) and Vimentin, as reflected in the indicators of the degree of mice pulmonary fibrosis,Telecommunicator Emergency Response Taskforce(TERT) as an index to reflect the telomerase activity were detect by immunohistochemical staining of paraffin sections oflung tissue. Compare the differences between the indicators in the control group and the model group of young mice and old mice, the results were analyzed using independent sample t-test statistical analysis and its correlation analysis.Results: The results of mice lung tissue paraffin sections with HE staining and Masson staining showed that tracheal injection of BLM induced pulmonary fibrosis in mice model. Aged mice pulmonary fibrosis lesions was more serious in young mice. Compared with young BLM group,E-Cadherin is lower in the elderly BLM group(P<0.05); compared with the control group,E-Cadherin is lower in the BLM model group(P<0.05), and reduced as time went by(P<0.05). Compared with young BLM group,α-SMA and Vimentin are higher in the elderly BLM group(P<0.05);compared with the control group, α-SMA and Vimentin are higher in the BLM model group(P<0.05), and increased as time went by(P<0.05). Compared with the young group,the fluctuation rate of TERT expression is higher in the elderly group, the positive rate of TERT expression change with time,increased at first and then decreased(P<0.001), namely,reached the peak on the fourteenth day and falling back to the degree of seventh day on the 28 day.Conclusion: Pulmonary fibrosis mice model can be induced by Intratracheal instillation of BLM(5mg/kg).Compared with young pulmonary fibrosis mice,aged mice are more serious in the degree of pulmonary fibrosis.In the pulmonary fibrosis mice,the expression of E-cadherin(E-cad) decreased, while the expression of alpha Smooth Muscle Actin(SMA) and Vimentin increased.The expression of Telecommunicator Emergency Response Taskforce(TERT) increased at first,while decreased next. The fluctuation of telomerase activity in aged mice is higher than that of young mice, and age can change the degree of pulmonary fibrosis by affecting the activity of telomerase in the pulmonary fibrosismodel.