[Effect of peroxisome proliferator-activated receptor-gamma on proliferation of airway smooth muscle cells in mice with asthma].

OBJECTIVE

To investigate the effects of peroxisome proliferator-activated receptor-gamma (PPARγ) agonist rosiglitazone on the expression of cyclin D1 in lung tissue, and the proliferation of airway smooth muscle cells (ASMCs) in mice with bronchial asthma.

METHODS

Thirty clean BALB/c mice were randomly divided into control group (n = 10), asthma group (n = 10), and rosiglitazone treatment group (n = 10). A mouse model of asthma was established by ovalbumin (OVA) sensitization and challenge. The treatment group received rosiglitazone (5 mg/kg) by gavage 1 hour before each challenge and the control group received saline instead of OVA sensitization and challenge. Leukocytes and eosinophils in bronchoalveolar lavage fluid (BALF) were counted under a microscope. Airway structural changes were observed by hematoxylin-eosin staining. Protein and mRNA expression levels of cyclin D1 were measured by immunohistochemical staining and RT-PCR. Perimeter of the basement membrane (Pbm), total bronchial wall area (WAt), airway smooth muscle area (WAm), and number of nuclei in ASMCs (N) were determined using image analysis software, and WAt/Pbm, WAm/Pbm, and N/Pbm were calculated.

RESULTS

Compared with the control group, the asthma group showed significant increases in the total number of leukocytes and percentage of eosinophils in BALF, as well as in the mRNA and protein expression of cyclin D1, but changes in these indices were significantly reduced in the rosiglitazone treatment group (P < 0.05). In addition, compared with the control group, the asthma group had significantly increased WAt/Pbm, WAm/Pbm, and N/Pbm, but rosiglitazone significantly decreased these ratios (P < 0.05).

CONCLISONS

Rosiglitazone may delay the process of airway remodeling by inhibiting the proliferation of ASMCs, so it can be used for preventing and treating chronic asthma.