Expression and significance of myeloid differentiation factor 88 in marrow dendritic cells in asthmatic rats with cigarette smoke exposure / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Smoking causes frequent asthma attacks, leading to a rapid decline in lung function in patients with asthma, and it can also reduce the therapeutic effect of glucocorticoids in patients with asthma. Therefore, the present study aimed to investigate the effect of cigarette smoke on the expression of myeloid differentiation factor 88 (MyD88) in marrow dendritic cells (DCs) in asthmatic rats, and to explore the molecular mechanism of cigarette smoke exposure on asthma by DCs.</p><p><b>METHODS</b>Forty Wistar rats were randomly divided into the following groups: control, smoke exposure, asthma, and asthma combined with smoke exposure. The animal model was established, and then rat bone marrow-derived DCs were collected. Additionally, rat spleen lymphocytes and bone marrow-derived DCs were cultured together for mixed lymphocyte responses. Interferon (IFN)-gamma and interleukin (IL)-4, IL-10, and IL-12 expressions were determined by enzyme-linked immunosorbent assay (ELISA). MyD88 expression was determined by Western blotting. The proliferation of lymphocytes was examined with methyl thiazolyl tetrazolium (MTT) colorimetric assay.</p><p><b>RESULTS</b>MyD88 expression was decreased in the asthma combined with smoke exposure group compared to the asthma group (P < 0.01), and IL-10 and IL-12 expressions were decreased in the asthma combined with smoke exposure group compared to control group (P < 0.01). In addition, DCs stimulating activity on allogeneic lymphocytes were significantly decreased in the smoke exposure combined with asthma group compared to the control and asthma groups (P < 0.01). After allogeneic mixed lymphocyte responses, IL-4 expression was increased and IFN-gamma was decreased in the asthma group and the asthma combined with smoke exposure group compared to control group (P < 0.01). IL-4 expression was increased and IFN-gamma was decreased in the asthma combined with smoke exposure group compared to the asthma group (P < 0.01). The study also showed that MyD88 expression was positively correlated with IL-12 and IFN-gamma expressions and the activity of lymphocytes (P < 0.01), and negatively correlated with IL-4 expression (P < 0.01).</p><p><b>CONCLUSIONS</b>Smoking aggravates asthma by weankening immunological mechanism. MyD88-dependent pathways may play a role in the immunological balance and activation of lymphocytes.</p>

Effects of angiotensin II receptor antagonist on expression of collagen III, collagen V, and transforming growth factor beta1 in the airway walls of sensitized rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Repeated attacks of bronchial asthma lead to different degrees of airway remodeling, the mechanism of which is not yet clear. Some evidences indicate that it is related to the excessive expression of some growth promotion factors. Angiotensin II is a polypeptide that may be involved in airway remodeling. To evaluate its role in airway remodeling in asthma, we observed the effects of an angiotensin II type 1 receptor antagonist (valsartan) on the expression of collagen III, collagen V, and transforming growth factor beta1 (TGF-beta1) mRNA and protein in the airway walls of sensitized rats.</p><p><b>METHODS</b>Forty Wistar rats were randomly divided into 5 groups: control group, sensitized group, and valsartan groups 1, 2, and 3. The rats in the sensitized group and in valsartan groups 1, 2, and 3 were sensitized and challenged with ovalbumin. Rats in control group were sensitized and challenged with 0.9% NaCl. Rats from valsartan groups 1, 2, and 3 were drenched with valsartan (10 microg, 20 microg, or 30 microg, respectively) at the time of the ovalbumin challenges. The expression of collagen III, collagen V, and TGF-beta1 protein were detected using immunohistochemical method in combination with image analysis methods. The expression of TGF-beta1 mRNA was detected by in situ hybridization.</p><p><b>RESULTS</b>The expression in the airways of collagen III and collagen V was significantly higher in rats from the sensitized group (7.73 +/- 0.81, 1.34 +/- 0.28) and from valsartan groups 1, 2, and 3 (5.73 +/- 0.64, 1.13 +/- 0.15; 4.96 +/- 0.51, 0.98 +/- 0.08; 4.43 +/- 0.35, 0.93 +/- 0.06, respectively) than those in the control group (2.65 +/- 0.38, 0.67 +/- 0.08, P < 0.05). In addition, collagen levels were significantly lower in valsartan groups 1, 2, and 3 than those from the sensitized group (P < 0.05). The expression of TGF-beta1 mRNA and protein in the airways was significantly higher in rats from the sensitized group (20.49% +/- 3.46%, 29.73% +/- 3.25%) and from valsartan groups 1, 2, and 3 (16.47% +/- 1.94%, 19.41% +/- 1.87%; 14.38% +/- 1.58%, 18.29% +/- 1.43%; 12.96% +/- 1.73%, 18.63% +/- 1.11%, respectively) than that from the control group (7.84% +/- 1.61%, 5.63% +/- 1.07%, P < 0.05). TGF-beta1 mRNA and protein levels were significantly lower in valsartan groups 1, 2, and 3 than that in the sensitized group (P < 0.05).</p><p><b>CONCLUSIONS</b>Angiotensin II receptor antagonist valsartan can suppress synthesis of collagen III and collagen V by downregulating TGF-beta1 mRNA and protein expression. Valsartan can decrease airway remodeling and could play a role in asthma therapy.</p>