A prospective randomized scanning electron microscopy study on the effect of a pneumoperitoneum on tumour cell implantation in nude mice

Abstract

ObjectiveThe aim of the study was to examine the influence of a CO2 pneumoperitoneum on intraperitoneal tumour cell implantation and on survival in the event of intra‐abdominal spread of tumour cells during laparoscopy in nude mice.Design6‐week‐old nude mice were stratified into three groups of 47 animals each. A CO2 pneumoperitoneum was induced by a microhysteroflator with an intraperitoneal pressure of 8 mmHg for 60 min in group 1 and 100 000 cells of a malignant mesothelioma, suspended in 2 ml of Ringer solution were injected intraperitoneally. Group 2 received an identical tumour cell load after laparotomy by midline incision. In the control group 3 tumour cells were injected only. After 1, 2, 6, 12, 24, 48, 72 and 96 h respectively four animals were killed and the entire peritoneum in all animals was examined by scanning electron microscopy. The survival time of the remaining 15 animals served as controlling arm.ResultsIn group 1, scanning electron microscopy showed that within 1 h mesothelial cells had become cuboidal, detached and condensed. The basement membrane was partly denuded. After 2 h this initial reaction reached its peak; tumour cells attached to the free basement membrane. None of those changes was seen in groups 2 and 3. It appears, that in group 1 intraperitoneal metastases were promoted by the CO2 pneumoperitoneum. The survival rate of group 1 was significantly reduced compared with that of group 2 and 3.ConclusionWe conclude that the technique of CO2 pneumoperitoneum promotes intraperitoneal tumour cell implantation and growth in nude mice.