Objective To observe the eotaxin expression of rat airway smooth muscle cells ( ASMCs) induced by serum from asthmatic rats, and explore the possible mechanism. Methods ASMCs isolated fromrat tracheas were cultured in vivo. Then they were treated with serum from asthmatic rats, or treated with serum and dexamethasone simultaneously. The level of eotaxin protein in supernatant and eotaxin mRNA in ASMCs were measured by ELISA and reverse transcription-polymerase chain reaction. The expression of cAMP in ASMCs was examined by radioimmunoassay. Results After the treatment with sensitized serum, the eotaxin level in supernatant and mRNA expression in ASMCs were significantly higher [ ( 107. 09 ±7. 12) ng/L vs. ( 0. 63 ±0. 56) ng/L, P lt; 0. 05; 1. 39 ±0. 04 vs. 0. 05 ±0. 01, P lt;0. 05] , and the level of cAMP in ASMCs was significantly lower compared with the control group [ ( 17. 58 ±3. 62) ng/L vs. ( 32. 39 ±3. 36) ng/L, P lt; 0. 05] . After intervened by the sensitized serum and dexamethasone simultaneously, the protein and mRNA expressions of eotaxin were lower compared with those intervened by sensitized serumalone [ ( 64. 18 ±4. 04) ng/L and 0. 77 ±0. 19] . The level of eotaxin in supernatant was negatively correlated with cAMP level in ASMCs ( r = - 0. 788, P lt; 0. 01) . Conclusions There is anautocrine function in ASMCs as inflammatory cells after stimulation with sensitized serum. Eotaxin may play an important roll in the pathogenesis of asthma via a cAMP-dependent pathway.
Objective To investigate the relevance and changes of mucosal immunity in asthma rats’lung, nose and intestine. Methods Twenty Wistar rats were randomly divided into a normal group and an asthma group. Asthma rat model was established by sensitization and challenge with ovalbumin. CD4 + ,CD8 + , eotaxin protein and its mRNA in rats’lung tissues, rhinal and intestinal mucosa were measured by immunohistochemical methods and situ hybridization. The content of sIgA in bronchoalveolar lavage fluid ( BALF) , nasopharyngeal washings and intestinal mucus supernatant were detected by enzyme-linked immunosorbent assay. Results Compared with the normal group, the levels of CD4 + , CD8 + in rats’lung tissues, rhinal and intestinal mucosa, the expression of eotaxin protein and mRNA in rats’lung tissues, the content of sIgA in nasopharyngeal washing, and the expression of eotaxin protein in intestinal mucosa were significantly higher in the asthma group( P lt; 0. 05) . There were no significant differences of other indices between the two groups. In the normal group, the eotaxin protein expression had a negative correlationbetween lung tissue and rhinal mucosa( r = - 0. 572, P = 0. 008) , and a positive correlation between intestinal and rhinal mucosa( r=0. 638, P =0. 002) . The eotaxin mRNA expression had a positive correlation between lung tissue and rhinal mucosa( r= 0. 502, P = 0. 024) , and a positive correlation between intestinaland rhinal mucosa( r=0. 594, P =0. 006) . In the asthma group, such a correlation was not found except the eotaxin protein expression which had a negative correlation between lung tissue and intestinal mucosa( r =- 0. 448, P = 0. 048) . Conclusions Mucosal immunity in lung, nose and intestine remains a dynamic balance. The balance of mucosal immunity is destroyed in asthma.
Objective To investigate the effects of diesel exhaust particles ( DEP) on the production of CCL11, CCL24 and CCL26 in asthmatic rats. Methods Fifty SD rats were randomly divided into five groups. Group A was an normal control group. The rats in group B, C, D, and E were sensitized and challenged by ovalbumin ( OVA) to establish asthma model. Then the rats in the group C, D, E were inhaled DEP for 1, 2, 3 weeks, respectively. Lung tissue and brouchoalveolar lavage fluid ( BALF) were collected for detection of CCL11, CCL24, and CCL26 expression by ELISA and q-RT-PCR. Results The transcription of CCL 24, CCL26 gene and the production of CCL24 and CCL26 protein increased significantly compared with the control group ( P lt;0. 05) , and were positively associated with the DEP inhalation time. However, CCL11 gene and protein expression were not changed significantly compared with the control. Conclusion The exposure to DEP can induce the production of CCL24 and CCL26 in the asthmaic rats, which might aggravateairway hyperresponsiveness.