Protective effect of heat shock protein 70 on lungs in newborn rats with hypoxic pulmonary hypertension

Abstract

Objective To investigate the protective effect of adenovirus mediated heat shock protein 70 (HSP70) on lungs in neonatal rats with hypoxic pulmonary hypertension(HPH). Methods One hundred and twenty-eight 7-10 d healthy Wistar neonatal rats were randomly divided into HPH model group and control group.HPH group was divided into saline group, empty virus group, and HSP70 group according to the transfection solution.HPH model was established in the hypoxia cabin of 80 mL/L nitrogen oxygen mixed gas after transfection.The mean pulmonary artery pressure(mPAP) was measured after 3, 7, 10 and 14 days of hypoxia in each group.The mRNA and protein expression of HSP70, hypoxia inducible factor-1 alpha(HIF-1α), endothelin-1(ET-1) and inducible nitric oxide synthase(iNOS) in the lung tissues of neonatal rats were detected by using reverse transcription-PCR and Western blot respectively. Results (1)The mPAP level was significantly higher in saline group(M, Q: 12.00, 2.50; 15.00, 2.00; 18.00, 1.75; 20.00, 2.25) than that in control group(M, Q: 9.50, 4.75; 10.50, 1.00; 13.00, 1.00; 15.50, 3.25), and the differences were significant(z=-3.28, -3.40, -3.34, -3.06, all P 0.05). (2)The expressions of HSP70 mRNA among the groups were statistically significant(F=6.321, 9.669, 6.333, all P<0.01), and the expressions of HSP70 protein also had significant difference(F=16.463, 3.637, 17.749, all P<0.01). (3)The level of HIF-1α mRNA in saline group was significantly higher than that of the control group, and the differences were statistically significant (q=4.312, 9.106, 6.151, all P<0.01); and the level of HIF-1α mRNA in empty virus group was also significantly higher than that in the control group, and the differences were statistically significant ( q=3.982, 9.235, 5.352, all P<0.01) in 3, 7, and 10 days; hypoxia in HSP70 group was lower than that of the empty virus group in 3, 7 days, and the differences were statistically significant (q=6.083, 11.031, all P<0.05). The level of ET-1 mRNA in saline group was significantly higher than that in the control group(q=5.112, 10.086, 6.264, all P<0.01), in empty virus group was significantly higher than that in the control group, and the differences were statistically significant (q=4.182, 12.238, 5.864, all P<0.01) in 3, 7, and 10 days, but in HSP70 group it was lower than that in the empty virus group in 3, 7, and 10 days, and the differences were statistically significant (q=6.912, 10.235, 7.021, all P<0.05). The level of iNOS mRNA in saline group was significantly higher than that of the control group, and the differences were statistically signi-ficant (q=4.998, 8.056, 5.369, all P<0.01), in empty virus group was significantly higher than that in the control group, and the differences were statistically significant (q=4.778, 10.138, 5.154, all P<0.01) in 3, 7, and 10 days, but in HSP70 group it was lower than that in the empty virus group in 3, 7, and 10 days, and the differences were statistically significant (q=7.819, 9.838, 6.156, all P<0.05). The level of HIF-1α protein in saline group was significantly higher than that of the control group in 3, 7, and 10 days, and the differences were statistically significant (q=3.146, 3.012, 4.106, all P<0.05), in empty virus group was significantly higher than that of the control group in 10 days, and the difference was statistically significant (q=3.468, P<0.05); but in HSP70 group it was lower than that in the empty virus group in 3, 7, and 10 days, and the differences were statistically significant (q=3.876, 4.108, 4.021, all P<0.05). The level of ET-1 protein of HSP70 group was lower than that of the saline group, the differences were statistically significant(q=3.367, 2.983, 3.246, all P<0.05), in HSP70 group was lower than that of the empty virus, and the differences were statistically significant (q=3.268, 2.678, 3.567, all P<0.05). The level of iNOS protein in saline group was significantly higher than that in the control group in 3, 7, and 10 days, and the diffe-rences were statistically significant (q=3.360, 3.567, 3.567, all P<0.05), but in HSP70 group it was lower than that in the empty virus group, and the differences were statistically significant (q=3.126, 3.908, 3.087, all P<0.05). Conclusion Adenovirus mediated HSP70 can improve the HSP70 expression in HPH, down-regulate the expression of HIF-1α, ET-1, iNOS, and reduce pulmonary arterial pressure. Key words: Heat shock protein 70; Adenovirus; Hypoxia inducible factor -1α; Hypoxic pulmonary hypertension; Neonatal rat