INCREASED SYNTHESIS OF TUMOR-NECROSIS-FACTOR-ALPHA IN UTERINE EXPLANTS FROM PREGNANT DIABETIC RATS AND IN PRIMARY CULTURES OF UTERINE CELLSIN HIGH GLUCOSE

The production of tumor necrosis factor-alpha (TNF-alpha) was investig ated in uterine explants from normal, diabetic, or insulin-treated dia betic pregnant rats. Explants from diabetic rats released more soluble TNF-alpha than did those in the other groups. The extent of this secr etion was correlated with blood glucose concentration at the time of e xplantation. The concentration of cell membrane-associated TNF-alpha i n the explants was not altered by diabetes. Daily insulin administrati on failed to normalize uterine TNF-alpha secretion despite correction of glycemia in the diabetic rats. Explants from normal pregnant rats c ultured in vitro with increasing concentrations of D-glucose showed a dose-dependent increase in TNF-alpha secretion. The production of TNF- alpha in high glucose was also tested in primary cultures of uterine c ells isolated from either immature or adult rats. TNF-alpha secretion was increased in high D-glucose but not in iso-osmolar concentrations of L-glucose, D-raffinose, D-galactose, or mannitol. Cell membrane-ass ociated TNF-alpha was not influenced by high D-glucose. Semiquantitati ve reverse transcription-amplification of RNA extracted from primary c ultures of uterine cells showed that the steady-state level of TNF-alp ha transcripts was increased by high D-glucose but not by high L-gluco se. The results are consistent with the hypothesis that hyperglycemia is instrumental in the overexpression of TNF-alpha in the diabetic ute rus. Because TNF-alpha has a demonstrated negative impact on embryonic growth, enhanced TNF-alpha synthesis in the pregnant uterus may contr ibute to the embryopathy associated with maternal diabetes.