关键词: 高血压, 肺性；烟雾吸入损伤；肺血管重塑；肌化；大鼠

Abstract:

Background　It is controversial that whether there is a direct causal association between cigarette smoke and pulmonary hypertension，a common pulmonary vascular disease.Studies have found that some smokers have remodeling of pulmonary small vessels in the early stage，even when the lung function is normal and there is no obvious hypoxia.However，the specific mechanism is still unclear.The remodeling of pulmonary small vessels is the main pathological mechanism of pulmonary hypertension.Some studies have shown that pulmonary vascular remodeling in experimental mice is related to the muscularization of pulmonary small vessels.Objective　To investigate the degree and significance of pulmonary arterioles muscularization in a rat model of pulmonary hypertension induced by cigarette smoke.Methods　This experiment was carried out from January to May 2018，16 healthy SD rats were randomly and equally divided into control group and model group.Rats in the model group received the intervention with cigarette smoke for 4 months for establishing.a pulmonary hypertension model，while those in the control group did not.At the end of 4 months，the activity，diet，hair and other general conditions of both groups of rats were observed，and the right ventricular systolic pressure and mean right ventricular pressure were measured.Right ventricular hypertrophy index，right ventricular weight to body weight（RV/BW） ratio were calculated.The expression of α-SMA in pulmonary small vessels was detected by immunohistochemistry to evaluate the degree of muscularization（non，partial and complete） of pulmonary arterioles.Results　The control group showed no abnormalities in their activities，diet，hair and other general conditions，while the model group showed obvious tiredness，often curled up in the corners，did not actively seek food，and their hair became more withered.The model group had higher mean right ventricular systolic pressure and average right ventricular pressure，and lower，average body weight than the control group（P<0.05）.The model group also showed greater average right ventricular hypertrophy index and RV/BW ratio（P<0.05）.Moreover，the model group showed lower proportion of non-muscularization in small pulmonary vessels（P<0.05）.The proportion of muscularized small pulmonary blood vessels in the model group was higher（P<0.05）.Specifically，the proportions of partial and complete muscularization were all higher（P<0.05）.Conclusion　Exposure to cigarette smoke may directly lead to pulmonary hypertension，which may be related to the aggravation of pulmonary arterioles muscularization.

Key words: Hypertension, pulmonary；Smoke inhalation injury；Right ventricular hypertrophy；Muscularization；Rats