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| Author(s): |
Juliana Dias Lourenço
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2016-04-07 |
| Examining board members: |
Fernanda Degobbi Tenorio Quirino dos Santos Lopes;
Carla Máximo Prado;
Rildo Aparecido Volpini
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| Advisor: | Fernanda Degobbi Tenorio Quirino dos Santos Lopes |
| Abstract | |
Introduction: We have previously showed that in an elastase-induced model of emphysema, the treatment with a serine protease inhibitor rBmTI-A, resulted in an improvement of tissue destruction in mice. Considering that smoking is the main risk factor for the development of COPD, and the cigarette smoke (CS) exposure is considered the best model to reproduce physiopathologic similarities with such disease in humans, this study aimed to verify the rBmTI-A treatment on the physiopathological processes involved in the development of cigarette smoke-induced emphysema. Methods: To induce pulmonary emphysema, animals were exposed to cigarette smoke (twice a day/ 30 minutes/ 5 days per week/ for 12 weeks) and the control animals were exposed to room air. Two treatment protocols with rBmTI-A inhibitor were performed. In the first one, animals received two administrations of rBmTI-A inhibitor or its vehicle (Saline Solution 0.9%) by nasal instillation, one dose at 24 hours after the end of exposure to tobacco smoke and another one, 7 days after the first instillation of the inhibitor. In the second protocol, animals received 3 rBmTI-A inhibitor administrations during the exposition time (1st dose: 24 hours before the start of exposure to cigarette smoke; 2nd dose: one month after the start of exposure, 3rd dose: two months after the start). After the end of exposure and treatment protocols, animals were submitted to procedures for collection of respiratory mechanics and evaluation of the Mean Linear Intercept (Lm). For the second protocol, we also measured the volume proportion of collagen and elastic fibers, the density of positive cells for MAC-2, MMP-12 and -9, TIMP-1, GP91phox and TNF-alfa in lung parenchyma by immunohistochemistry. Also, we evaluated the measurement of polymorphonuclear cells and the lung gene expression for MMP-12 and 9 by RT-qPCR. Results and Discussion: Treatment with the serine protease inhibitor rBmTI-A attenuated the development of emphysema only in the second protocol, when it was administered during exposure to cigarette smoke. Although Smoke-rBmTIA and Smoke-VE groups showed an increase of Lm measure compared to Control groups, there were a decrease in the Smoke-rBmTIA group compared to Smoke-VE group. The same response was observed for the analysis of volume proportion of elastic and collagen fibers in parenchyma. In addition, we observed an increase of macrophages, MMP-12, MMP-9 and TNF-alfa; in groups exposed to cigarette smoke, but treatment with rBmTI-A inhibitor only decreased the number of positive cells for MMP-12. We did not observed difference between the experimental groups in lungs gene expression for MMP- 12 and 9, and the same behavior was observed for the amount of polymorphonuclear cells in parenchyma. Moreover, we observed an increase of GP91phox and TIMP-1 in groups treated with rBmTI-A. Conclusions: These results suggest that rBmTI-A inhibitor was not effective for treatment of parenchymal lesions after established disease. However, this inhibitor attenuated the development of disease when administered during the induction of emphysema, possibly by an increase of GP91phox and TIMP-1, accompanied by a decrease of MMP-12 (AU) | |
| FAPESP's process: | 13/04488-8 - Treatment Evaluation with a serinoprotease inhibitor in a smoke-induced emphysema model |
| Grantee: | Juliana Dias Lourenço |
| Support Opportunities: | Scholarships in Brazil - Master |