Medicina / Ciências Médicas e da Saúde

Dissertações de Mestrado

Resumo

Introduction: Pediatric pulmonary arterial hypertension (PH) presents certain specific features, however there is a lack of experimental models to study the physiopathology of PH in this specific age group.

Aim: To characterize hemodynamic, morphometric and histological progression as well as expression of neurohumoral factors and regulators of cardiac transcription in an infantile model of PH induced by monocrotaline (MCT).

Methods: Eight-days-old Wistar rats were randomly injected with MCT (30mg/Kg, sc, n=95) or equal volume of saline solution (n=92). Different time points after injection were defined for analysis. Hearts and lungs were collected for morphometric characterization and stained with picrosirius red for assessment of the RV and LV collagen type I and type III ratio, RV collagen volume fraction (days 1, 3, 7, 14 and 21) and pulmonary vessels wall thickness (days 7, 14 and 21). mRNA quantification was undertaken for BNP, ET-1, HOP and Islet1 (days 1, 7 and 21). Animals were instrumented for biventricular hemodynamic recording on days 7, 14 and 21 after treatment.

Results: Animals treated with MCT at the 8th day of life presented RV hypertrophy since day 7 after MCT injection. There were no differences on the RV collagen volume fraction or collagen type I and type III ratio. Pulmonary vascular remodeling and PH were present on day 21, which were accompanied by an increased expression of BNP, ET-1, HOP and Islet1.
Conclusion: The model of MCT induced pediatric PH can be useful for physiopathological studies and to test new therapeutic targets in this age group

 

Palavras chave: Pulmonary hypertension, Pediatric, BNP, Endothelin-1, HOP, Islet1.
 

 

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