INTRODUCTION L APAROSCOPIC SURGICAL TECHNIQUES have been in- creasingly preferred to classic laparotomy by surgeons since 1987. The procedure has gained wide acceptance be- cause it results in less pain, a shorter hospital stay, and the avoidance of larger abdominal incisions as well as exten- sive intra-abdominal dissections. Additionally, the postop- erative recovery period is much shorter and the postopera- tive stress response is less than its open counterpart. 1 The patients treated with laparoscopy regain their daily activity quicker and have better cosmetic results. 2,3 The pneumoperitoneum is used to facilitate the visual- ization of intra-abdominal organs and to lift the abdomi- JOURNAL OF LAPAROENDOSCOPIC & ADVANCED SURGICAL TECHNIQUES Volume 18, Number 3, 2008 © Mary Ann Liebert, Inc. DOI: 10.1089/lap.2007.0023 The Comparative Effects of Pneumoperitoneum on Apoptosis and p53 Expression in Gastrointestinal Organs YÜKSEL ARIKAN, MD, 1 MURAT TOSUN, MD, 2 SEZGIN YILMAZ, MD, 1 VOLKAN SAYKOL, MD, 1 and ZAFER SÖYLEMEZ, MD 3 ABSTRACT Background: Laparoscopic surgical techniques have been increasingly preferred to classic la- parotomy by surgeons since 1987. The pneumoperitoneum is often used to facilitate the intra-ab- dominal field, but it carries the risk of its ischemic potential and has differences [l2]of metabolic, inflammatory, and infectious consequences, depending on the pressure set and kind of gas used. However, the mechanisms related with the cell injury observed after laparoscopy are still unknown. The aim of this study was to evaluate the effects of different pressures of CO 2 on apoptosis and p53 expression in small and large intestines and the stomach. Materials and Methods: In total, 30 Sprague-Dawley male rats were used in the study. CO 2 is in- sufflated into the intra-abdominal cavity through a angiocatheter cannule by an insufflator set at two different pressures of 10 and 20 mm Hg during 60 minutes. In the control group, the cannule was inserted into the intra-abdominal cavity without any other surgical procedure and no gas was insufflated. After 60 minutes, the rats were sacrificed and a laparotomy was performed. The small and large intestines and stomach were excised. The samples were histologically processed and an immunohistochemical analysis was performed. Results: The results of the study revealed that the number of apoptotic cells in intra-abdominal organs we studied increased in proportion to the CO 2 pressure level. However, the p53 expression was detected only in the stomach. Conclusions: Our study showed that the number of apoptotic cells rises in parallel to the increase in intra-abdominal pressure following the CO 2 pneumoperitoneum in rat large and small intestine and stomach. Although the apoptosis was activated by the p53 pathway in the stomach, it was not so in the large and small intestine. Departments of 1 General Surgery, 2 Histology and Embryology, and 3 Genetics, The Faculty of Medicine, Afyonkarahisar Kocatepe University, Afyonkarahisar, Turkey. 365