[The role of alveolar macrophages in airway remodeling in asthmatic rats].
OBJECTIVE
To study the role of alveolar macrophages (AM) in the processes of airway remodeling in asthmatic rats.


METHODS
Forty-eight young male Sprague-Dawley rats (Grade II) were divided randomly into a control group (A group), a 3 day asthma group (B group), a 14 day asthma group (C group) and a 30 day asthma group (D group). The rats were sensitized and challenged by ovalbumin to establish the asthmatic model. AM were purified from bronchoalveolar lavage. The content of tumor necrosis factor-alpha (TNF-alpha) in AM was measured by enzyme-linked immunosorbent assay, prostaglandin E2 (PGE2) by radioimmunoassay, matrix metalloproteinase-9 mRNA (MMP-9 mRNA) and tissue inhibitor of metalloproteinase-1 mRNA (TIMP-1 mRNA) by hybridization in situ. The total bronchial wall area (WAt) and the smooth muscle area (WAm) were measured by image analysis system. The WAt and the WAm were quantified per unit length of basement membrane (Pbm).


RESULTS
The bronchial wall thickness and the smooth muscle thickness of D group [(85 +/- 9) microm2/microm, (28.6 +/- 4.9) microm2/microm] were significantly higher than those of A group [(67 +/- 10) microm2/microm, (16.8 +/- 2.4) microm2/microm, t = 2.938, 3.227, all P < 0.01]. The contents of TNF-alpha and PGE2 in D group [(0.68 +/- 0.25) microg/L, (0.122 +/- 0.030) microg/L] were significantly higher than those in A group [(0.37 +/- 0.09) microg/L, (0.079 +/- 0.018) microg/L, t = 2.683, 3.016, all P < 0.01]. When A group was compared with B group [(0.74 +/- 0.29) microg/L, (0.120 +/- 0.028) microg/L] and C group [(0.71 +/- 0.23) microg/L, (0.117 +/- 0.028) microg/L], there was no significant difference (t = 1.624, 0.472, all P > 0.05) and (t = 0.935, 0.533, all P > 0.05). The contents (light density) of MMP-9 mRNA and TIMP-1 mRNA in D group (0.346 +/- 0.033, 0.361 +/- 0.040) were significantly higher than C group (0.279 +/- 0.015, 0.259 +/- 0.015, t = 2.574, 2.716, all P < 0.01), and so did D group and B group (0.183 +/- 0.025, 0.136 +/- 0.014, t = 2.913, 3.017, all P < 0.01), D group and A group (0.104 +/- 0.007, 0.109 +/- 0.008, t = 3.632, 3.487, all P < 0.01). There were significant correlations between the contents of MMP-9 mRNA and WAt (r = 0.693, P < 0.01), between MMP-9 mRNA and WAm (r = 0.738, P < 0.01), between TIMP-1 mRNA and WAt (r = 0.823, P < 0.01), and between TIMP-1 mRNA and WAm (r = 0.876, P < 0.01).


CONCLUSIONS
AM and AM-derived cytokines are associated with airway remodeling in asthmatic rats.
Wang
Chuan-xia
CX
Affiliated Yuying Children's Hospital, Wenzhou Medical College, Wenzhou 325027, China.
Li
Chang-chong
CC
Luo
Yun-chun
YC
Li
Meng-rong
MR
D056151:Airway Remodeling; D000818:Animals; D001249:Asthma / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D016207:Cytokines / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism
D016207:Cytokines; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1