[Expression and role of early growth response gene-1 in experimental silicosis of rat].
OBJECTIVE
To study the expression and location of early growth response gene-1 (Egr-1), transforming growth factor-beta(1) (TGF-beta(1)), fibronectin (FN) in silicotic rat and to discuss the role of Egr-1 in the development of silicosis.


METHODS
Silicotic animal model of rat was established, and the expressions of Egr-1, TGF-beta(1), FN in various lung cells of silicotic rat were analysed by using immunohistochemical technique (SP) and the image analysis.


RESULTS
The expressions of Egr-1 in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell in lung silicotic tissue (gray values: 118.58 +/- 5.65 - 168.52 +/- 5.67) were higher than those of controls (gray values: 166.23 +/- 5.23 - 188.12 +/- 8.35) during 1 - 28 days, and the expression was mainly in nucleus; the expressions of TGF-beta(1) in these cells (gray values: 123.49 +/- 5.65 - 170.24 +/- 3.56) were also higher than those of controls (166.53 +/- 6.25 - 198.56 +/- 4.53), and the expression was mainly in cytoplasm. The expressions of FN in bronchial epithelial cell, pulmonary macrophage and alveolar epithelial cell (gray values: 150.32 +/- 6.54 - 201.54 +/- 7.38) were lower, while those in interstitial cell (gray values: 121.43 +/- 5.65 - 167.55 +/- 6.35) were higher than those of controls. The changes of TGF-beta(1) and Egr-1 expression level in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell were synchronous during the experiment (1 - 28 days). Both of them were correlated with each other (r = 0.61, P < 0.01), while the expression of FN was not correlated with Egr-1, but correlated to TGF-beta(1) in interstitial cell (r = 0.46, P < 0.01).


CONCLUSIONS
Silicon dioxide could up-regulate the expression of nuclear transcription factor Egr-1 in several kinds of cell in lung. The activated Egr-1 may coordinate the expression of TGF-beta(1) and FN to regulate the development of silicosis.
Chu
Ling
L
Department of Pathology, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Li
Xiang
X
Hu
Yong-bin
YB
Wang
Jin-sheng
JS
Zheng
Hui
H
Zeng
Qing-fu
QF
D000818:Animals; D004268:DNA-Binding Proteins / Q000032:analysis / Q000502:physiology*; D004195:Disease Models, Animal; D051766:Early Growth Response Protein 1; D005353:Fibronectins / Q000032:analysis / Q000502:physiology; D017874:Immediate-Early Proteins / Q000032:analysis / Q000502:physiology*; D007150:Immunohistochemistry; D008168:Lung / Q000737:chemistry / Q000503:physiopathology; D051381:Rats; D012829:Silicosis / Q000209:etiology* / Q000378:metabolism; D014157:Transcription Factors / Q000032:analysis / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000502:physiology
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D005353:Fibronectins; D017874:Immediate-Early Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta