Serum SP-D is a marker of lung injury in rats.
Pulmonary surfactant protein D (SP-D) is expressed in alveolar type II and bronchiolar epithelial cells and is secreted into alveoli and conducting airways. However, SP-D has also been measured in serum and is increased in patients with acute respiratory distress syndrome, pulmonary fibrosis, and alveolar proteinosis. To demonstrate that SP-D can be measured in rat serum, we instilled rats with keratinocyte growth factor, which produces type II cell hyperplasia and an increase in SP-D in bronchoalveolar lavage fluid (BALF). To evaluate serum SP-D as a biomarker of lung injury, we examined several injury models. In rats treated with 1 unit of bleomycin, serum SP-D was elevated on days 3, 7, 14, and 28 after instillation, and SP-D mRNA was increased in focal areas as detected by in situ hybridization. However, there was no increase in whole lung SP-D mRNA when the expression was normalized to whole lung 18S rRNA. After instillation of 2 units of bleomycin, the serum levels of SP-D were higher, and SP-D was also increased in BALF and lung homogenates. In another model of subacute injury, serum SP-D was increased in rats treated with paraquat plus oxygen. Finally to evaluate acute lung injury, we instilled rats with HCl; SP-D was increased at 4 h after instillation. Our data indicate that serum SP-D may be a useful indicator of lung injury and type II cell hyperplasia in rats.
Pan
Tianli
T
Department of Medicine, National Jewish Medical and Research Center, 1400 Jackson Street, -K625, Denver, CO 80206, USA.
Nielsen
Larry D
LD
Allen
Martin J
MJ
Shannon
Kathleen M
KM
Shannon
John M
JM
Selman
Moises
M
Mason
Robert J
RJ
D000818:Animals; D000964:Antimetabolites, Antineoplastic; D015415:Biomarkers; D001761:Bleomycin; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D015870:Gene Expression; D006023:Glycoproteins / Q000032:analysis / Q000097:blood* / Q000235:genetics; D006540:Herbicides; D006851:Hydrochloric Acid / Q000494:pharmacology; D006965:Hyperplasia; D007322:Instillation, Drug; D008171:Lung Diseases / Q000097:blood* / Q000139:chemically induced / Q000473:pathology; D008297:Male; D010100:Oxygen / Q000494:pharmacology; D010269:Paraquat; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000473:pathology; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants / Q000032:analysis / Q000097:blood* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D013047:Specific Pathogen-Free Organisms
D000964:Antimetabolites, Antineoplastic; D015415:Biomarkers; C496455:Fgf7 protein, rat; D006023:Glycoproteins; D006540:Herbicides; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D001761:Bleomycin; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D010269:Paraquat; D006851:Hydrochloric Acid; D010100:Oxygen