Gene expression of surfactant protein-A and thyroid transcription factor-1 in lungs of rats exposed to silicon-carbide whisker in vivo.
Intratracheal instillation studies have shown that exposure to silicon carbide whisker (SiCW), an asbestos substitute, produces pulmonary fibrotic changes, suggesting that SICW might have a fibrogenic potential. It is thought that surfactant protein is a good biomarker of lung injury and pulmonary fibrotic activity. In order to explore whether or not surfactant protein is associated with lung disorder through exposure to SiCW, we examined the expression of SP-A, SP-C and thyroid transcription factor-1 (TTF-1), a common transcription factor of SP-A and SP-C mRNA in lungs exposed to SiCW. Male Wistar rats were administered 2 mg or 10 mg of SiCW suspended in saline by a single intratracheal instillation, and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months after the intratracheal instillation. RNA was subsequently extracted from the lungs, and expression of SP-A, SP-C and TTF-1 mRNA from the lungs was observed by reverse transcription-polymerase chain reaction (RT-PCR). Exposure to 2 mg of SiCW showed a decrease in mRNA of SP-A and TTF-1 at 6 months, but exposure to 10 mg of SiCW showed decreased levels of SP-A and TTF-1 mRNA at 3 d and 6 months. On the other hand, 2 mg of SiCW increased the level of SP-C mRNA from 3 d to 3 months, and 10 mg of SiCW decreased the levels of SP-C mRNA in the rat lungs at 3 d, 1 month and 6 months. No clear tendency to the expression of SP-C was observed, but the patterns of expression of TTF-1 and SP-A were similar. These data suggest that SP-A and TTF-1 are associated with not only the acute phase but also the chronic phase in lungs exposed to SiCW.
Morimoto
Yasuo
Y
Institute of Industrial and Ecological Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi, Kitakyushu 807-8555, Japan.
Ding
Li
L
Oyabu
Takako
T
Kim
Heungnam
H
Ogami
Akira
A
Hirohashi
Masami
M
Nagatomo
Hiroko
H
Yamato
Hiroshi
H
Akiyama
Izumi
I
Hori
Hajime
H
Higashi
Toshiaki
T
Tanaka
Isamu
I
D000818:Animals; D015870:Gene Expression; D008171:Lung Diseases / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics*; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017655:Silicon Compounds / Q000633:toxicity*; D018709:Statistics, Nonparametric; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D037662:Pulmonary Surfactant-Associated Protein A; D017655:Silicon Compounds; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors