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[Regulative mechanism of dexamethasone on Toll-like receptor 4 signal transduction of infant asthma rat].
Zhonghua Er Ke Za Zhi. 2006 Dec; 44(12):937-40.ZE

Abstract

OBJECTIVE

Eosinophilic airway inflammation is one of the basic characteristics of allergic asthma. Toll-like receptor is one of the most important innate immunity pattern recognition receptors. Glucocorticoids (GCS) are still the most effective treatment for asthma. However, few reports of studies on regulatory mechanism of GCS on the innate immunity system are available. The mechanism of effects of GCS on TLR4 is unclear. The present study aimed at understanding the effect of dexamethasone (DXM) on change of TLR4 and mechanism of regulatory effect of TLR4 on eosinophil (EOS) apoptosis.

METHODS

Twenty-seven Sprague-Dawley (SD) rats (age 28 to 42 days, body weight 120 to 180 gram) were randomly divided into the control group, asthma group and DXM group with 9 in each. Asthma model rats were sensitized with the mixture of ovalbumin (OVA, 1 mg) and Al (OH)(3), 100 mg on day 1 and day 8, repeatedly exposed to aerosolized OVA after day 15, once a day for three days and continued for 30 minutes at every time. During the sensitization stage, 100 microg/ml DXM were prepared with DXM group for every other day, and the same doses DXM were prepared for every day on the stage of challenge. The histopathological changes of lung tissues were observed with light microscope (LM). EOS and other inflammatory cells in bronchoalveolar lavage fluid (BALF) were counted; the concentrations of OVA-sIgE in serum were measured by using "sandwich" ELISA; The expressions of TLR4 mRNA were determined by in situ hybridization, the apoptosis of EOS was detected by TUNEL.

RESULTS

(1) LM showed many inflammatory cells infiltration around the bronchi and blood vessels, bronchus mucus increased, airway epithelium damage and desquamation, and airway mucous plugs in asthma group, whereas DXM group showed significantly milder changes. (2) Inflammationary cells count in BALF of asthma group was significantly higher as compared to control group (P < 0.01); compared with asthma group, the total cell count, EOS absolute count and EOS% were all significantly decreased in DXM group [(2.14 +/- 0.10) x 10(9)/L, (4.78 +/- 1.23) x 10(7)/L, (2.17 +/- 0.25)%]. (3) Levels of OVA-sIgE in serum of asthma group [(83.40 +/- 6.80) microg/ml] were significantly higher than those of the control group [(14.38 +/- 4.25) microg/ml] (P < 0.01), while those of DXM group [(45.02 +/- 7.47) microg/ml] were significantly lower than asthma group (P < 0.0 1). (4) There were no significant differences in TLR4 mRNA detected by in situ hybridization between control group (24.71 +/- 0.85) and asthma group (25.81 +/- 3.56) (P > 0.05); but it significantly increased in DXM group (29.86 +/- 3.92) as compared to asthma group. (5) The percentages of apoptotic EOS in asthma group [(7.39 +/- 1.93)%] were significantly lower than those in control group [(9.06 +/- 1.52)%] (P < 0.01); and significantly higher in DXM group [(13.33 +/- 1.09)%] than in asthma group (P < 0.01). There were significantly positive correlations between TLR4 mRNA and the percentage of apoptotic EOS (r = 0.612, P < 0.01).

CONCLUSION

DXM can decrease OVA-sIgE level, induce EOS apoptosis, which may correlate with the activation of TLR4 signal transduction.

Authors+Show Affiliations

Department of Respiratory Diseases, Yuying Children's Hospital of Wenzhou Medical College, Wenzhou 325027, China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

English Abstract
Journal Article

Language

chi

PubMed ID

17254466

Citation

Su, Miao-shang, et al. "[Regulative Mechanism of Dexamethasone On Toll-like Receptor 4 Signal Transduction of Infant Asthma Rat]." Zhonghua Er Ke Za Zhi = Chinese Journal of Pediatrics, vol. 44, no. 12, 2006, pp. 937-40.
Su MS, Li CC, Lin L, et al. [Regulative mechanism of dexamethasone on Toll-like receptor 4 signal transduction of infant asthma rat]. Zhonghua Er Ke Za Zhi. 2006;44(12):937-40.
Su, M. S., Li, C. C., Lin, L., Zheng, J. S., Zheng, Y. M., Guan, X. J., Zhang, W. X., & Luo, Y. C. (2006). [Regulative mechanism of dexamethasone on Toll-like receptor 4 signal transduction of infant asthma rat]. Zhonghua Er Ke Za Zhi = Chinese Journal of Pediatrics, 44(12), 937-40.
Su MS, et al. [Regulative Mechanism of Dexamethasone On Toll-like Receptor 4 Signal Transduction of Infant Asthma Rat]. Zhonghua Er Ke Za Zhi. 2006;44(12):937-40. PubMed PMID: 17254466.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Regulative mechanism of dexamethasone on Toll-like receptor 4 signal transduction of infant asthma rat]. AU - Su,Miao-shang, AU - Li,Chang-chong, AU - Lin,Li, AU - Zheng,Ji-shan, AU - Zheng,Yang-ming, AU - Guan,Xiao-jun, AU - Zhang,Wei-xi, AU - Luo,Yun-chun, PY - 2007/1/27/pubmed PY - 2010/6/4/medline PY - 2007/1/27/entrez SP - 937 EP - 40 JF - Zhonghua er ke za zhi = Chinese journal of pediatrics JO - Zhonghua Er Ke Za Zhi VL - 44 IS - 12 N2 - OBJECTIVE: Eosinophilic airway inflammation is one of the basic characteristics of allergic asthma. Toll-like receptor is one of the most important innate immunity pattern recognition receptors. Glucocorticoids (GCS) are still the most effective treatment for asthma. However, few reports of studies on regulatory mechanism of GCS on the innate immunity system are available. The mechanism of effects of GCS on TLR4 is unclear. The present study aimed at understanding the effect of dexamethasone (DXM) on change of TLR4 and mechanism of regulatory effect of TLR4 on eosinophil (EOS) apoptosis. METHODS: Twenty-seven Sprague-Dawley (SD) rats (age 28 to 42 days, body weight 120 to 180 gram) were randomly divided into the control group, asthma group and DXM group with 9 in each. Asthma model rats were sensitized with the mixture of ovalbumin (OVA, 1 mg) and Al (OH)(3), 100 mg on day 1 and day 8, repeatedly exposed to aerosolized OVA after day 15, once a day for three days and continued for 30 minutes at every time. During the sensitization stage, 100 microg/ml DXM were prepared with DXM group for every other day, and the same doses DXM were prepared for every day on the stage of challenge. The histopathological changes of lung tissues were observed with light microscope (LM). EOS and other inflammatory cells in bronchoalveolar lavage fluid (BALF) were counted; the concentrations of OVA-sIgE in serum were measured by using "sandwich" ELISA; The expressions of TLR4 mRNA were determined by in situ hybridization, the apoptosis of EOS was detected by TUNEL. RESULTS: (1) LM showed many inflammatory cells infiltration around the bronchi and blood vessels, bronchus mucus increased, airway epithelium damage and desquamation, and airway mucous plugs in asthma group, whereas DXM group showed significantly milder changes. (2) Inflammationary cells count in BALF of asthma group was significantly higher as compared to control group (P < 0.01); compared with asthma group, the total cell count, EOS absolute count and EOS% were all significantly decreased in DXM group [(2.14 +/- 0.10) x 10(9)/L, (4.78 +/- 1.23) x 10(7)/L, (2.17 +/- 0.25)%]. (3) Levels of OVA-sIgE in serum of asthma group [(83.40 +/- 6.80) microg/ml] were significantly higher than those of the control group [(14.38 +/- 4.25) microg/ml] (P < 0.01), while those of DXM group [(45.02 +/- 7.47) microg/ml] were significantly lower than asthma group (P < 0.0 1). (4) There were no significant differences in TLR4 mRNA detected by in situ hybridization between control group (24.71 +/- 0.85) and asthma group (25.81 +/- 3.56) (P > 0.05); but it significantly increased in DXM group (29.86 +/- 3.92) as compared to asthma group. (5) The percentages of apoptotic EOS in asthma group [(7.39 +/- 1.93)%] were significantly lower than those in control group [(9.06 +/- 1.52)%] (P < 0.01); and significantly higher in DXM group [(13.33 +/- 1.09)%] than in asthma group (P < 0.01). There were significantly positive correlations between TLR4 mRNA and the percentage of apoptotic EOS (r = 0.612, P < 0.01). CONCLUSION: DXM can decrease OVA-sIgE level, induce EOS apoptosis, which may correlate with the activation of TLR4 signal transduction. SN - 0578-1310 UR - https://www.unboundmedicine.com/medline/citation/17254466/[Regulative_mechanism_of_dexamethasone_on_Toll_like_receptor_4_signal_transduction_of_infant_asthma_rat]_ L2 - http://journal.yiigle.com/LinkIn.do?linkin_type=pubmed&amp;issn=0578-1310&amp;year=2006&amp;vol=44&amp;issue=12&amp;fpage=937 DB - PRIME DP - Unbound Medicine ER -