| Objective: To study the effect of HSP70 regulating Bcl-2 and Bax on pulmonary vascular endothelial cell apoptosis and pulmonary artery pressure in neonatal rats with hypoxia pulmonary the hypertension(HPH).Methods: A total of 128 Wister neonatal rats were randonly divided in to control group and the hypoxia group,and HPH model was established in hypoxia group which were subsequently divided into HPH group,HSP70+HPH group and KNK437+HSP70+HPH group based on the different intervention method.In HSP70+HPH and KNK437+HSP70+HPH group,Ad-HSP70-EGFP(enhanced green fluorescent protein labeled HSP70 adenoviral vector)were injected through oral tracheal intubation.In HSP and control group,Ad-CON-EGFP(enhanced green fluorescent protein labeled empty adenovirus vector)were injected through oral tracheal intubation,and KNK437+ HSP70+HPH group was intraperitoneally injected with the HSP70 inhibitor KNK437 daily,and the control group was fed under normoxia condition.Average right ventricular systolic pressure(RVSP)was tested in 3,7,10,14 days in each group,changes in pulmonary vascular endothelial cell apoptosis was observed and the expression levels of HSP70 、 Bcl-2 、 Bax in lung tissue were tested.Results: 1)Immunofluorescence: It was observed that the green fluorescence(labeled adenoviral vector)decreased gradually with the prolongation of time,and the green fluorescence was located around the bronchioles,but no obvious fluorescence was found in all groups after14 days of hypoxia;2)Apoptosis of pulmonary vascular endothelial cells: Apoptosis of endothelial cells was observed in hph group after hypoxia for 3 days,but decreased after hypoxia for 14 days.Apoptosis was observed in HSP70 + HPH group after 7 days of hypoxia,and the degree of apoptosis and proliferation was lower than that of hph group at the same age.Apoptosis was observed in the group of KNK437 + HSP70 + HPH after hypoxia for 3 days,and the degree of apoptosis was higher than that in the group of HSP70 + HPH at the same age;3)Average RVSP: The average RVSP in HPH group was higher than that of the control group at each the observation time point(P<0.05),indicating that the model establishment was successful;the average RVSP in HSP70+HPH group was lower than that of the HPH group and KNK437+ HSP70 in 3,7,and 10 days of hypoxia,there was no significant difference compared with the control group(P<0.05);4)The expression of HSP70: the expression of HSP70 in the HPH group was the higher than that of the control group in 3,7 and 10 days of hyppoxia(P<0.05),the expresssion of HSP70 in the HSP70+HPH group was higher than that of the HPH group in 3 and 7 days of hypoxia(P<0.05),and there was no statistical difference in 10 and 14 days of hypoxia(P >0.05).The expression of HSP70 in KNK437+HSP70+HPH group was lower than HSP70+HPH group and HPH group in 3,7,and 10 days of the hypoxia(P<0.05);5)The expression of Bcl-2 and Bax: The expression of Bcl-2 in the HPH groups was lowerr than that of the control group(P<0.05),and the expressionn of Bax was the higher than that of the control group(P<0.05).The expression of the Bcl-2at the different observation time point in the HSP70+HPH group was higher than that of the HPH group(P<0.05),and the expression of Bax in 3 days of hypoxia was lower than that of the HPH group(P<0.05);the expression of Bcl-2 in the KNK437+HSP70+HPH group was lower than that in the HSP70+HPH group in 3,7,10 days of hypoxia(P<0.05),and the expression of Bax was higher than that in the HSP70+HPH group in 3 days of hypoxia(P<0.05).Conclusion: Adenovirus-mediated increase in the expression of exogenous HSP70 in the lung tissue of neonatal rats may be through up-regulation of Bcl-2 and down-regulation of Bax,which inhibited pulmonary endothelial cell apoptosis in the early stage of hypoxia and reducing pulmonary artery pressure,which plays a protective role in development of HPH in neonatal rat. |
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