A PROSPECTIVE RANDOMIZED SCANNING ELECTRON-MICROSCOPY STUDY ON THE EFFECT OF A PNEUMOPERITONEUM ON TUMOR-CELL IMPLANTATION IN NUDE-MICE

Objective The aim of the study was to examine the influence of a CO2 p neumoperitoneum on intraperitoneal tumour cell implantation and on sur vival in the event of intra-abdominal spread of tumour cells during la paroscopy in nude mice. Design 6-week-old nude mice were stratified in to three groups of 47 animals each. A COB pneumoperitoneum was induced by a microhysteroflator with an intraperitoneal pressure of 8 mmHg fo r 60 min in group 1 and 100 000 cells of a malignant mesothelioma, sus pended in 2 ml of Ringer solution were injected intraperitoneally. Gro up 2 received an identical tumour cell load after laparotomy by midlin e incision. In the control group 3 tumour cells were injected only. Af ter 1, 2, 6, 12, 24, 48, 72 and 96 h respectively four animals were ki lled and the entire peritoneum in all animals was examined by scanning electron microscopy. The survival time of the remaining 15 animals se rved as controlling arm. Results In group 1, scanning electron microsc opy showed that within 1h mesothelial cells had become cuboidal, detac hed and condensed. The basement membrane was partly denuded. After 2h this initial reaction reached its peak; tumour cells attached to the f ree basement membrane. None of those changes was seen in groups 2 and 3. It appears, that in group 1 intraperitoneal metastases were promote d by the CO2 pneumoperitoneum. The survival rate of group 1 was signif icantly reduced compared with that of group 2 and 3. Conclusion We con clude that the technique of CO2 pneumoperitoneum promotes intraperiton eal tumour cell implantation and growth in nude mice.