关键词: 肉鸡, BQ123, 内皮素, 肺动脉高压, 肺血管重塑

Abstract: The effect of BQ123,a selective ETA-receptor antagonist, on pulmonary vascular structural remodeling induced by low ambient temperature was investigated through observing the dynamic change of pulmonary arterioles medial thickness and pulmonary blood vessel endometry area caused by proliferous smooth muscle cells in broiler chickens. Two hundred 16-day old commercial broiler chickens were randomly divided into 4 groups as follows: 50 birds were exposed to normal temperature(20 ℃) and injected normal saline to abdominal cavity as control group, 50 birds were exposed to low temperature (7~9 ℃) and injected normal saline to abdominal cavity as low temperature group，50 birds were exposed to low temperature and injected low dose BQ123 to abdominal cavity as low dose BQ123 group，and 50 birds were exposed to low temperature and injected high dose BQ123 to abdominal cavity as high dose BQ123 group. Pulmonary arterial pressure (PAP ) was determined as index of pulmonary hypertension. The measurement of ratio of vessel wall area to vessel total area (WA/TA) and mean medial thickness in pulmonary arterioles (mMTPA) were accomplished by using the microscopic image analysis program. The results showed as follows,(1)BQ123 significantly inhibited the increase of mPAP(kPa): high dose BQ123 group was lower than low temperature group at 23 days(P＜0.05);high dose BQ123 group and low dose BQ123 group were obviously lower than low temperature group at 30 days(P＜0.01);(2)BQ123 inhibited the increase of WA/TA of pulmonary arterioles: the value of 30~50 μm pulmonary arterioles of low temperature group was obviously higher than that of low dose BQ123 group and high dose BQ123 group (P＜0.01); It bears an analogy to the differences between groups in the other ranks of pulmonary arterioles;(3)BQ123 made mMTPA of pulmonary arterioles to be reduced: to 30~50 μm pulmonary arterioles,at the age of 23, low temperature group was obviously higher than low dose BQ123 group and high dose BQ123 group(P＜0.01); at the age of 30, low temperatue group was higher than low dose BQ123 group(P＜0.05) and obviously higher than high dose BQ123(P＜0.01), and low dose BQ123 was higher than high dose BQ123(P＜0.05);It bears an analogy to the differences between groups in less than 30 μm pulmonary arterioles; It was not obviously different between groups to 50~120 μm pulmonary arterioles. It can be concluded that BQ123 can inhibit pulmonary vascular structural remodeling and pulmonary artery hypertension induced by low ambient temperature in broiler chickens. ET may play a key role in pulmonary vascular structural remodeling and pulmonary artery hypertension induced by low ambient temperature in broiler chickens.

Key words: broiler, BQ123, endothelin, pulmonary arterial pressure, pulmonary vascular structural remodeling