EFFECT OF HUMAN RECOMBINANT TUMOR-NECROSIS-FACTOR-ALPHA AND PENTOXIFYLLINE ON THE ULTRASTRUCTURE OF TYPE-II ALVEOLAR EPITHELIAL-CELLS IN PREGNANT AND NONPREGNANT RABBITS

An ultrastructural study was made of the morphological changes in type II alveolar epithelial cells (epII) of pregnant and non-pregnant rabb its, given human recombinant tumour necrosis factor-alpha (TNF-alpha) to induce experimental shock. TNF-alpha (biological activity 2-4 x 10( 7) U/mg of protein) was injected once intraperitoneally, at a dose of 100 mu g/kg body weight. The moderating effects of pentoxifylline (PTX F), given as four intraperitoneal doses (20 mg/kg) at 12-h intervals b efore injection of TNF-alpha, were also assessed. In animals treated w ith PTXF + TNF-alpha and with TNF-alpha only, damage to lung tissue, p articularly to epII, was observed. Many epII had empty lamellar bodies . These changes were particularly distinct in the rabbits given TNF-al pha only. PTXF limited the degree of damage to epII, particularly that shown by the lamellar bodies. There were no significant differences i n degree of damage to alveolar epithelial cells between pregnant and n onpregnant rabbits. Thus, the increased risk of severe complications d ue to shock observed in pregnancy may not be associated with changes i n the surfactant system. However, further studies, particularly bioche mical analysis of the surfactant, are necessary to confirm this. (C) 1 997 W.B. Saunders Company Limited.