Acute changes in peritoneal morphology and transport properties with infectious peritonitis and mechanical injury

Acute changes in peritoneal morphology and transport properties with infectious peritonitis and mechanical injury. Peritoneal clearance studies were performed in rats undergoing acute peritoneal dialysis. Some of these animals were then exposed to laparotomy and mechanical drying of the peritoneum. Peritoneal clearance studies were repeated at intervals up to 11 days. Another group of rats was placed on daily peritoneal dialysis and allowed to spontaneously develop peritonitis which was not treated. These rats underwent peritoneal transport studies at differing durations of infection. In all groups, animals were sacrificed at the time of the last transport studies for morphological assessment of the peritoneum by light microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed similar decreases in drainage volume and increases in glucose absorption and protein losses with both infection and drying. Both types of injury resulted in extensive mesothelial structural changes. While drying caused mainly denudation of the mesothelial surface, infectious peritonitis was associated with separation of mesothelial cells, and the appearance of numerous white blood cells between and on mesothelial cells. Exposure to peritoneal dialysis alone had no obvious effects on anatomy. Although changes in the peritoneal microcirculation and deeper structures cannot be excluded as contributing to peritoneal transport alterations, the findings suggest that alterations of mesothelium might explain some of the changes in peritoneal transport properties under the conditions of these studies. Modifications aigues de la morphologie et des proprietes de transport du peritoine par peritonite infectieuse et lesion mecanique. Des etudes de clearance peritoneale ont ete entreprises chez des rats en dialyse peritoneale aigue. Certains de ces animaux etaient soumis a une laparotomie et a un sechage mecanique du peritoine. Les etudes de clearance peritoneale etaient repetees a des intervalles allant jusqu'a 11 jours. Un autre groupe de rat etait place en dialyse peritoneale journaliere, et il pouvait developper spontanement une peritonite qui n'etait pas traitee. Chez ces rats ont ete effectuees des etudes de transport peritoneal a differents stades d'infection. Dans tous les groupes, les animaux etaient sacrifies lors de la derniere etude de transport afin d'etudier morphologiquement le peritoine par microscopie optique, microscopie electronique a balayage, et microscopie electronique par transmission. Les resultats ont montre des diminutions du volume de drainage et des augmentations de l'absorption du glucose et des pertes proteiques identiques avec l'infection ou le sechage. Les deux types de lesions ont entraine des modifications structurelles mesotheliales importantes. Tandis que le sechage entrainait principalement une denudation de la surface mesotheliale, la peritonite infectieuse etait associee a une separation des cellules mesotheliales, et a l'apparition de nombreux globules blancs entre et sur les cellules mesotheliales. L'exposition a la dialyse peritoneale seule n'avait pas d'effets anatomiques evidents. Bien que la contribution aux alterations du transport peritoneal de modifications de la micro-circulation peritoneale et des structures plus profondes ne puisse etre exclue, ces resultats suggerent que les alterations du mesothelium pourraient expliquer certaines des modifications des proprietes de transport peritoneal dans les conditions de ces etudes.