Forty male SD rats were randomly divided into 5 groups and exposed to normoxia (C group) or exposed to
hypoxia for 3, 7, 14 or 21 d (H(3),
H(7), H(14), H(21) group), respectively. Mean pulmonary arterial pressure (mPAP), vessel morphometry and right ventricle
hypertrophy index (RVHI) were measured.
Reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization were used to determine the expression of
mRNA. Immunohistochemistry and Western blot were used to determine the expression of
mRNA.
RESULTS: The level of mPAP [(21.7 +/- 2.4) mm Hg, 1 mm Hg = 0.133 kPa], the ratio of vascular wall thickness to external diameter [WA%, (43.9 +/- 5.3)%] and pulmonary artery media thickness [PAMT, (10.0 +/- 0.7) microm] were significantly higher in
H(7) group than those in C group [(16.6 +/- 1.6) mm Hg, (36.3 +/- 4.8)% and (8.5 +/- 1.3) microm respectively, q value were 5.591, 4.082, 2.929, respectively, all P < 0.05]. These parameters reached a high level and remained stable on H(14) group, and RVHI was significantly higher in H(14) group [(27.6 +/- 1.4)%] than in C group [(23.6 +/- 2.9)%, q = 5.817, P < 0.05]. HIF-1alpha
protein was barely positive in C group (0.080 +/- 0.009), but markedly up-regulated in H(3) group (0.196 +/- 0.018, compared with C group q = 18.864, P < 0.05), reaching its peak in
H(7) group (0.203 +/- 0.022), and then declined slightly in H(14) and H(21) group. HIF-1alpha
mRNA increased marginally in H(14) group (0.176 +/- 0.019, compared with C group q = 5.401, P < 0.05, 0.139 +/- 0.017). PHD1 and PHD2
mRNA (0.260 +/- 0.031, 0.196 +/- 0.023) and
protein (0.244 +/- 0.030, 0.205 +/- 0.025) were positive in C group. PHD2
mRNA and
protein were up-regulated in H(3) group (0.246 +/- 0.023, 0.235 +/- 0.025, compared with C group q value was 5.268, 3.046, respectively, all P < 0.05), reaching its peak in H(14) group whereas PHD1
protein declined in H(14) group (0.210 +/- 0.023, compared with C group q = 3.885, P < 0.05) without significant
mRNA change. PHD3
mRNA and
protein were detected at low level in C group (0.110 +/- 0.013, 0.153 +/- 0.019), but markedly up-regulated in H(3) group (0.259 +/- 0.024, compared with C group q = 15.831, P < 0.05), and then PHD3
mRNA remained at high level while PHD3
protein declined in H(14) and H(21) group (0.206 +/- 0.025, 0.189 +/- 0.019, compared with
H(7) group q value was 6.441, 8.526, respectively, all P < 0.05). Linear correlation analysis showed that HIF-1alpha
mRNA and
protein were positively correlated with mPAP. There was a positive correlation between HIF-1alpha
protein and PHD2, PHD3
mRNA (r value was 0.580, 0.690, respectively, all P value was 0.000) but a negative correlation between HIF-1alpha
protein and PHD2
protein (r = -0.704, P < 0.05).
CONCLUSIONS: