Influence of laparoscopy and laparotomy on systemic and peritoneal T lymphocytes in a rat model.

Little is known about the local influence of pneumoperitoneum on components of the peritoneal immune defense mechanisms. We investigated CD25, CD4, CD8 expression and CD4/CD8 ratio of systemic and peritoneal T lymphocytes in a rat model. Fifty male Sprague Dawley rats underwent laparotomy, CO2 pneumoperitoneum, helium pneumoperitoneum, gasless laparoscopy, or anesthesia only. After 24 h venous blood was drawn, and peritoneal lavage was performed to harvest CD25+, CD4+, and CD8+ cells. CD4+, CD8+, and CD25+ T lymphocytes were determined. A significantly lower peritoneal CD4/CD8 ratio was found after CO2 and helium laparoscopy than in controls (P<0.05). However, no significant differences in systemic CD4/CD8 ratio or peritoneal or systemic CD25 expression were found between the different operative groups. Pneumoperitomeum independently of the insufflation gas (CO2 or helium) leads to comparable postoperative immunmodulations of peritoneal CD4+ and CD8+ T-lymphocytes. The mechanical pressure of the pneumoperitoneum seems to aggravate peritoneal T lymphocytes.