Glucose decreases steady state mRNA content of hydrophobic surfactant proteins B and C in fetal rat lung explants

Exp Lung Res. 1999 Jan-Feb;25(1):69-79. doi: 10.1080/019021499270439.

Abstract

The streptozotocin-induced diabetic (STZ-DB) rat model is associated with fetal hyperglycemia, but with low to normal plasma insulin concentration. Because surfactant protein (SP) mRNA content in fetal rat lung is decreased in STZ-DB pregnancy, we investigated the effect of increasing concentrations of glucose on SP gene expression in lung organ cultures. SP mRNA content (SP-A, SP-B, SP-C) was assessed by Northern blot analysis in fetal day 20 lung explants (term = 22 days) cultured for 44 hours in medium containing 10, 25, 50, or 100 mM glucose. Our findings were (1) No consistent alteration in SP-A mRNA content was observed at different glucose concentrations (P > .05); (2) SP-B and SP-C mRNA content were reduced in a dose-dependent manner when glucose concentration was increased from 10 mM to 100 mM. The mRNA content, compared to 10 mM glucose, decreased to 50-60% at 25 mM glucose, to 20-25% at 50 mM glucose, and to lower than 10% at 100 mM glucose (P < .01). These findings indicate that the decrease in SP-B and SP-C mRNA in fetuses of STZ-DB rats may be, in part, due to a direct effect of hyperglycemia, whereas the decrease in SP-A mRNA content in STZ-DB rats appears to be due to other effects of diabetes in pregnancy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Autoradiography
  • Dose-Response Relationship, Drug
  • Female
  • Glucose / toxicity*
  • Lung / drug effects*
  • Lung / embryology*
  • Lung / metabolism
  • Organ Culture Techniques
  • Pregnancy
  • Proteolipids / antagonists & inhibitors
  • Proteolipids / biosynthesis*
  • Proteolipids / genetics
  • Pulmonary Surfactants / antagonists & inhibitors
  • Pulmonary Surfactants / biosynthesis*
  • Pulmonary Surfactants / genetics
  • RNA, Messenger / drug effects
  • RNA, Messenger / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Proteolipids
  • Pulmonary Surfactants
  • RNA, Messenger
  • Glucose