Objective      To determine the effects of angiotensin (Ang) Ⅱ and losartan

an antagonist of angiotensin type 1 receptor（AT1R）

on the production of collagen type Ⅰ in human passively sensitized airway smooth muscle cells.       Methods      After human airway smooth muscle cells were isolated from normal bronchial tissue samples

and primarily cultured and identified by immunofluorescence staining of α-actin. T

he obtained cells were divided into the following 4 groups: ① passively sensitized group: 10％serum from asth-matic patients; ② passively sensitized+AngⅡ group: 10％serum from asthmatic patients+AngⅡ (final concentration of 10

-7

mol/L); ③ passively sensitized+losartan group: 10％serum from asthmatic patients+losartan (final concentration of 10

-6

mol/L); ④ passively sensitized+AngⅡ+losartan group: 10％serum from asthmatic patients+AngⅡ (final concentration of 10

-7

mol/L)+losartan (final concentration of 10

-6

mol/L). The effect of AngⅡ and losartan on the collagen type Ⅰ mRNA expression in the passively sensitized HASMCs was detected by real-time RT-PCR

and its protein content was analyzed by ELISA.       Results      Compared to control group

the mRNA expression and protein release of collagen type Ⅰ in AngⅡ-induced group (10

-7

mol/L for 24 h) was significantly higher（

P

0.01). Losartan treatment produced a significantly inhibitory effect on the expression of mRNA and protein synthesis (

P

0.01).       Conclusion      AngⅡ induces the synthesis of collagen type Ⅰ by human passively sensitized airway smooth muscle cells

which might be through binding with AT1R.