Expression of leukemia inhibitory factor in airway epithelial tissue of asthmatic rats

Abstract

In order to investigate the expression of leukemia inhibitory factor (LIF) in airway epithelial tissues of normal and asthmatic rats, the influence of dexamethasone and the role of LIF in pathogenesis of asthma, 30 Sprague-Dawley (SD) rats were randomly divided into 3 groups (10 for each group): normal group, asthma model group, and dexamethasone-interfered group. In asthma model group and dexamethasone-interfered group, asthma rat models were established by intraperitoneal (i.p.) injection of 10% ovalbumin (OVA) and challenge with 1% OVA via inhalation. Rats in dexamethasone-interfered group were pretreated with dexamethasone (2 mg/kg, i.p) 30 min before each challenge. The expression of LIF protein in lung was detected by immunohistochemistry. The results showed that LIF protein was mainly expressed in cytoplasm of bronchial epithelial cells. The expression of LIF protein in the airway epithelial tissue of asthma model group was significantly higher than that in normal group and dexamethasone-interfered group (P<0.01), but there was no significant difference between normal group and dexamethasone-interfered group (P>0.05). It was concluded that the expression of LIF was increased significantly in the airway epithelial tissue of the asthma rats, and dexamethasone could down-regulate the expression of LIF. It was suggested that LIF might play an important role in the pathogenesis of asthma as an inflammation regulator.

Keywords

bronchial asthma / leukemia inhibitory factor / immunohistochemistry

References

[1] KnightD. A., LydellC. P., ZhouD. e. a1.. Leukemia inhibitory factor (LIF) and LIF receptor in human lung: Distribution and regulation of LIF release. Am J Respir Cell Mol Biol, 1999, 20: 834-841

[2] ZhengX. Y., KnightD. A., ZhouD. e. a1.. Leukemia inhibitory factor is synthesized and released by human eosinophils and modulates activation state and chemotaxis. J Allergy Clin Immunol, 1999, 104: 136-144

[3] GaoY. D., XiongS. D., XuY. J., et al.. The role of nitrogen monoxidum (NO) in potassium channel of bronchial smooth muscle cell in asthma rat. Zhong Hua Jie He He Hu Xi Za Zhi (Chinese), 2003, 10(26): 615-618

[4] ItoA., MiyakeM., MorishitaM., et al.. Dexamethasone reduces lung eosinophilia, and VCAM-1 and ICAM-1 expression induced by Sephadex beads in rats. Eur J Pharmacol, 2003, 468(1): 59-66

[5] TofarisG. K., PattersonP. H., JessenK. P., et al.. Denervated schwann cells attract macrophages by secretion of leukemia inhibitory factor ( LIF ) and monocyte chemoattractant protein-1 in a process regulated by interleukin-6 and LIF. J Neurosci, 2002, 22(15): 6696-6703

[6] EscaryJ. L., PerreauJ., DumenilD., et al.. Leukemia inhibitory factor is necessary for maintenance of haematopoietic stem cells and thymocyte stimulation. Nature, 1993, 363: 361-364

[7] GyotokuE., MoritaE., KameyoshiY., et al.. The IL-6 family cytokines, interleukin-6, interleukin-11, oncostatin M, and leukemia inhibitory factor, enhance mast cell growth through fibroblast-dependent pathway in mice. Arch Dermatol Res, 2001, 293: 508-514

[8] IkezonoT., WuT., YaoX. L., et al.. Leukemia inhibitory factor induces the 85-kDa cytosolic Phospholipase A2 gene expression in cultured human bronchial epithelial cells. Biochim Biophys Acta, 1997, 1355: 121-130

[9] LingM. J., HuC. P., WuE. S., et al.. Expression of leukemia inhibitory factor in lung of asthma rat. Zhonghua Jie He He Hu Xi Za Zhi (Chinese), 2003, 26: 727-728

[10] ChabaudM., FossiezF., TaupinJ. L., et al.. Enhancing effect of IL-17 on IL-1-induced IL-6 and leukemia inhibitory factor production by rheumatoid arthritis synoviocytes and its regulation by Th2 cytokines. J Immunol, 1998, 161: 409-414

[11] GrossetC., TaupinJ. L., LemercierC., et al.. Leukemia inhibitory factor expression is inhibited by glucocorticoids through posttranscriptional mechanisms. Cytokine, 1999, 11: 29-36