Objective      To investigate the roles of transforming growth factor β (TGF-β) and connective tissue growth factor (CTGF) in right cardiac ventricular fibrosis and hypertrophy under hypobaric hypoxia.       Methods      A total of 50 SD male rats (8 weeks old

weighting 188.6±19.3 g) were randomly and equally divided into control group (normoxia)

and hypobaric hypoxia groups for 3

7

14 and 28 d

respectively. The rats in hypobaric hypoxia groups were housed in a hypobaric chamber simulating high altitude at 6 000 m above sea level for corresponding days. Right ventricle hypertrophy index (RVHI) was evaluated by the ratio of weight of the right ventricle to the weight of the left ventricle plus interventricular septum. Expression of type Ⅰ collagen (COL-Ⅰ)

TGF-β and CTGF at mRNA and protein levels in the right ventricle was measured by real-time PCR and Western blotting. The correlation of the duration of hypobaric hypoxia with the expression of TGF-β

CTGF with COL-Ⅰ and RVHI were analyzed.       Results      Compared with normoxic control group

RVHI was significantly elevated in the hypoxia groups

with those of 7

14 and 28 d hypoxia groups more significance (P0.05). The mRNA and protein levels of COL-Ⅰ were significantly increased in the right cardiac ventricular of the rats after exposure under hypobaric hypoxia for 7

14 and 28 d (P0.05). The protein levels of TGF-β (3.68±0.17) and CTGF (8.73±0.96) were significantly increased in the 3 d hypoxia group (P0.05)

and so were those of TGF-β (0.93±0.15) and CTGF (12.62±0.14) under hypoxia for 28 d (P0.05). But there were no differences in the expression of the 2 cytokines between the rats under hypoxia for 7 and 14 d (P0.05). With the increase of duration of hypobaric hypoxia

the mRNA levels of TGF-β and CTGF were significantly correlated to RVHI (P0.05) and to COL-Ⅰ mRNA level except for 28 d hypoxia group (P0.05)

and the mRNA level of TGF-β was positively associated with that of CTGF (P0.05).       Conclusion      With the increase of the hypoxia duration

the expression of TGF-β is increased and then decreased

while the expression trend of CTGF is increased and then decreased

and the 2 cytokines are involved in the fibrosis and hypertrophy of rat right cardiac ventricule under hypobaric hypoxia exposure.