RESUMO
To investigate the effect of T(3)-induced pulmonary hypertension on endothelin (ET) production and genes expression of ET-1, ET(A) and ET(B) receptors (ET(A)R and ET(B)R) during rearing, semiquantitative RT-PCR and enzyme immunometric assay were performed in the heart ventricles and serum, respectively. The ET-1 and its receptor genes were expressed in the right and left ventricles of control and T(3)-treated broilers at 12, 28 and 49 days of age. There were significant (P<0.05) reductions of the relative amounts of ET-1 (in both ventricles) and ET(A)R (in the right ventricle) mRNAs at 28 and 49 days of age, in T(3)-treated broilers compared to controls. The relative amounts of ET(B)R mRNA in the right and left ventricles did not significantly differ between control and T(3)-treated broilers at any age. The serum level of ET was significantly (P<0.05) increased in T(3)-treated chickens at 28 and 49 days of age when compared with that of the control. It is concluded that ET-1, ET(A)R and ET(B)R genes are normally expressed in the heart ventricles of broilers. It is likely that increased serum level of ET and decreased ET-1/ET(A)R genes expression in the ventricles are involved in the heart dysfunction of broiler chickens with developmental pulmonary hypertension.
Assuntos
Galinhas , Endotelina-1/metabolismo , Hipertensão Pulmonar/veterinária , Receptor de Endotelina A/metabolismo , Receptor de Endotelina B/metabolismo , Tri-Iodotironina/toxicidade , Animais , Endotelina-1/genética , Regulação da Expressão Gênica , Hipertensão Pulmonar/induzido quimicamente , Técnicas Imunoenzimáticas , Miocárdio/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor de Endotelina A/genética , Receptor de Endotelina B/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterináriaRESUMO
To compare Endothelin (ET) production and genes expression of ET-1 and ET(A) receptor (ET(A)R) between broiler and layer chickens during rearing, semi-quantitative RT-PCR and enzyme immunometric assay were performed in the heart ventricles and serum. There were gradual elevations of ET-1 and ET(A)R mRNAs in the left ventricle of broiler and layer chicken groups that were mainly significant (P<0.05) at 28, 35 and 42 days of age with compared to previous days whereas were not significant between two groups. These gradual elevations of ET-1 and ET(A)R mRNAs were also observed in the right ventricle that were significant (P<0.05) at 28, 35 and 42 days of age in broilers and 42 days of age in layers with compared to previous days. Increasing of these mRNAs in the right ventricle of broiler chickens were significantly (P<0.05) more than layer chickens at 28, 35 and 42 days. Serum ET in broilers was significantly (P<0.05) higher than layer chickens at 28 and 42 days of age. It is concluded that circulating ET and cardiac ET-1, ET(A)R genes expression is higher in broiler chickens than in layer chickens particularly after 21 days of age. It is probably that these breed differences make broiler chickens to be more susceptible to Endothelin related-cardiomyopathies such as congestive heart failure and ascites.