Effect of human recombinant tumour necrosis factor-α and pentoxifylline on the ultrastructure of type II alveolar epithelial cells in pregnant and non-pregnant rabbits

Abstract

An ultrastructural study was made of the morphological changes in type II alveolar epithelial cells (epII) of pregnant and non-pregnant rabbits, 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 micrograms/kg body weight. The moderating effects of pentoxifylline (PTXF), given as four intraperitoneal doses (20 mg/kg) at 12-h intervals before injection of TNF-alpha, were also assessed. In animals treated with PTXF + TNF-alpha and with TNF-alpha only, damage to lung tissue, particularly to epII, was observed. Many epII had empty lamellar bodies. These changes were particularly distinct in the rabbits given TNF-alpha only. PTXF limited the degree of damage to epII, particularly that shown by the lamellar bodies. There were no significant differences in degree of damage to alveolar epithelial cells between pregnant and non-pregnant rabbits. Thus, the increased risk of severe complications due to shock observed in pregnancy may not be associated with changes in the surfactant system. However, further studies, particularly biochemical analysis of the surfactant, are necessary to confirm this.