Effect of thyroid hormone (T3)-responsive changes in surfactant apoproteins on surfactant function during sepsis.
BACKGROUND
Long surfactant phospholipids are altered during sepsis; the role of surfactant apoproteins is unknown. This study investigates the effect of cecal ligation and puncture (CLP) on surfactant functional effectiveness and apoprotein transcriptional activity with or without T3 replacement.


METHODS
Male Sprague Dawley rats underwent sham laparotomy or CLP with or without T3 replacement. Lung compliance, surfactant adsorption, and surface tension were measured with a surfactometer. Surfactant apoproteins A, B, and C (SP-A, SP-B, SP-C) mRNA was quantified by Northern blot analysis.


RESULTS
Lung compliance was significantly decreased by sepsis; initial surface tension and adsorption values in CLP animals reflected apoprotein dysfunction. Sepsis decreased SP-A mRNA levels and increased SP-B mRNA; SP-C mRNA were unchanged. T3 treatment improved compliance, adsorption, and ST isotherms in septic animals.


CONCLUSIONS
T3 attenuated sepsis-induced surfactant dysfunction and SP-A and SP-B transcriptional changes during sepsis. This suggests an interaction between the thyroid, surfactant apoproteins, and lung surfactant functional effectiveness and requires further study.
Raafat
A M
AM
Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan, USA.
Franko
A P
AP
Zafar
R
R
Dulchavsky
S A
SA
Diebel
L N
LN
Ksenzenko
S
S
D000818:Animals; D015152:Blotting, Northern; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D008170:Lung Compliance; D008297:Male; D011510:Proteolipids / Q000032:analysis* / Q000187:drug effects; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis* / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000188:drug therapy*; D014158:Transcription, Genetic; D014284:Triiodothyronine / Q000627:therapeutic use*
D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D014284:Triiodothyronine