[An experimental study on pulmonary vascular inflammation in a rat model of chronic bronchitis and emphysema]

To study the characteristics of intra-acinar pulmonary artery inflammation in rats with chronic bronchitis (CB) and emphysema and to evaluate the protective and therapeutic effects of erythromycin (EM).

Eighteen male Wistar rats were divided into 3 groups randomly, 6 rats per group, a normal control group (group A), a CB and emphysema group (group B), and an EM-treatment group (group C). The rat model of CB and emphysema was established by intratracheal instillation of lipopolysaccharide (LPS) and daily exposure to cigarette smoke. After 8 weeks the pathological and morphometric changes in the lung were analyzed.

(1) The inflammation in intra-acinar pulmonary arteries, described as total inflammatory cells per square millimeter of adventitia (cell/mm(2)), was different among the three groups, (33 +/- 6) cell/mm(2) in group A, (158 +/- 68) cell/mm(2) in group B, and (54 +/- 7) cell/mm(2) in group C; the difference being significant between group A and group B and between group B and group C (t = 9.6, 9.2, all P < 0.01). (2) The morphometric characteristics of intra-acinar pulmonary muscular arteries: the thickness of intra-acinar pulmonary muscular arteries, described as intimal area per total area, was significantly different among the groups (t = 9.7, 9.4, all P < 0.01), (21 +/- 4)% in group A, (37 +/- 3)% in group B, and (30 +/- 1)% in group C.

There was inflammatory reaction largely of lymphocyte infiltration in the adventitia of intra-acinar pulmonary arteries in rats with CB and emphysema. Inflammatory reaction in intra-acinar pulmonary arteries plays an important role in vascular remodeling. EM may prevent the inflammation and remodeling of intra-acinar pulmonary arteries to some degree.