[Prophylactic effect of retinoic acid on chronic obstructive pulmonary emphysema in rats]

To evaluate the effect and molecular mechanism of retinoic acid (RA) in preventing experimental pulmonary emphysema in rats.

Thirty-six Wistar rats were randomly divided into three groups, the normal group(A), the model group (B) and the RA treated group (C). Rats in group B group were exposed to cigarette smoke, and group C was treated with RA. Pulmonary function indices and histopathological changes were evaluated. The enzymatic activity of gelatinases was measured by ELISA, and the expression of gelatinases and the proliferating cell nuclear antigen (PCNA) was examined by immunohistochemical method.

Compared with group A, group B presented significant differences in FEV(0.3),FEV(0.3)/FVC and FRC [(5.1 +/- 0.4) ml vs (6.0 +/- 0.3) ml, (71 +/- 10) ml/s vs (87 +/- 3) ml/s, (7.2 +/- 2.2) ml vs (2.9 +/- 1.1) ml (P < 0.01)];the enzymatic activity [(1.06 +/- 0.23)ng/ml vs (0.53 +/- 0.17)ng/ml, (0.960 +/- 0.230)ng/ml vs (0.300 +/- 0.090)ng/ml] and the expression of gelatinases were also markedly elevated(P < 0.01). In comparison with group B, the pulmonary function indices in group C [(5.2 +/- 0.4)ml, (81 +/- 5) ml/s, (6.1 +/- 2.7)ml/s] were improved (P < 0.05); the enzymatic activity [(0.83 +/- 0.23)ng/ml, (0.570 +/- 0.010)ng/ml] and the expression of gelatinases were decreased, while the PCNA index staining (93 +/- 4 vs 53 +/- 6) was increased (P < 0.01).

RA can prevent the development of pulmonary emphysema in rats.