Effect of carbon dioxide pneumoperitoneum on the severity of acute pancreatitis: An experimental study in rats

Effects of carbon dioxide pneumoperitoneum on exocrine and endocrine functions, and oxidative state of rat pancreas

We investigated the effects of increased intra-abdominal pressure during laparoscopy on the endocrine and exocrine functions, oxidative stress and histopathology of the pancreas in rats. We established three experimental groups of eight animals. Group 1 was the untreated control. Forth other two groups, pneumoperitoneum with CO₂ was established for 60 min at 6 mm Hg for group 2 and 12 mm Hg for group 3; groups 2 and 3 animals were allowed to re-perfuse for 30 min. Amylase, glucagon and insulin levels were analyzed in blood samples and insulin:glucagon ratio was calculated. Histopathology and malondialdehyde assay were performed on pancreatic tissue samples. Histological damage scores for vasocongestion were increased significantly in groups 2 and 3 compared to group 1. Histological damage scores for inflammatory cell infiltration were increased significantly in group 3 compared to group 1. Malondialdehyde levels were increased significantly in group 3 compared to group 1. We found no significant differences among groups for serum amylase levels or histological damage scores for hemorrhage. Insulin and glucagon levels, and the insulin:glucagon ratio was increased significantly in group 3 compared to groups 1 and 2. We found that in rats routine laparoscopy caused increased serum insulin and glucagon levels, and histopathological changes that indicated ischemia-reperfusion injury to the pancreas.

Minimally invasive surgery and oxidative stress response: what have we learned from animal studies?

Oxidative stress (OS) is an integral part of the surgical stress response. Minimally invasive surgery causes less trauma, and thus attenuated stress response is anticipated. However, the pneumoperitoneum or pneumoretroperitoneum is implicated in free radical production. This study reviewed available data on the impact of minimally invasive surgery on OS response of animal models in a systematic way. Databases were searched up to and including January 2010. Most of the studies investigated the effect of pneumoperitoneum on OS, 3 studies investigated the effect of pneumoretroperitoneum on OS. There was a great heterogeneity on experimental conditions including animal models, measured OS markers, methods, and time periods of measurement. Published animal data do not allow a reliable conclusion on the effect of minimally invasive surgery on OS because of the great heterogeneity of experimental conditions. Besides, most studies focus on the effect of pneumoperitoneum, without taking into consideration the effect of less surgical trauma.

Laparoscopy can aggravate the severity of pancreatitis in an experimental rat model

PURPOSE

Over the past decade, laparoscopic techniques have markedly evolved, and it has been shown that minimally invasive surgery can provide a safe, effective, and less traumatic management of various surgical diseases. Additionally, it is well known that pancreatitis itself also produced severe oxidative tissue injury by increasing levels of reactive oxygen species. This study therefore aimed to investigate the effects of pneumoperitoneum on the severity of pancreatitis in a rat model of acute pancreatitis induced by cerulein.

MATERIALS AND METHODS

Thirty-five Wistar albino rats were divided into five groups with seven rats in each. Experimental pancreatitis was induced using intraperitoneal injection of cerulein. The first group received open laparotomy. Groups 2-5 were treated with 5, 10, 15, and 20 mm Hg, respectively, achieved by applying pressure and waiting for 60 minutes. After this waiting interval, all of the rats were sacrificed; blood samples were taken by intracardiac puncture for biochemical assays, and pancreatic tissue samples were taken for light microscope analysis. Histopathology was scored according to edema, granulation, polymorphonuclear leukocytes, and mononuclear cells in all groups.

RESULTS

Great increases in malondialdehyde and reduced glutathione levels were seen in all of the groups in which pancreatitis was induced. In Group 2-5, more significant increases were detected than in the open laparotomy group (P<.005). In the histopathological examination, Groups 2-5 showed more inflammatory cell infiltration, edema, and granulation tissue than the open laparotomy group (P<.005).

CONCLUSIONS

It is useful to remember the parameters of the medical treatment of pancreatitis. While surgical treatment is being decided, we think that the process of all kinds of surgery, including laparoscopic surgery, can increase the severity of pancreatitis.

CO2 abdominal insufflation decreases local and systemic inflammatory response in experimental acute pancreatitis

OBJECTIVES

Acute pancreatitis (AP) is a serious disease that is amplified by an associated systemic inflammatory response. We investigated the effect of CO2 pneumoperitoneum on the local and systemic inflammatory response in AP.

METHODS

Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Carbon dioxide pneumoperitoneum was applied for 30 minutes before the induction of AP. Inflammatory parameters were evaluated in the peritoneum (ascites, cell number, and tumor necrosis factor alpha [TNF-alpha]), serum (amylase, TNF-alpha, interleukin-6 [IL-6], and IL-10), pancreas (myeloperoxidase [MPO] activity, cyclo-oxygenase 2 and inducible nitric oxide synthase expression, and histological diagnosis), liver, and lung (mitochondria dysfunction and MPO activity).

RESULTS

Abdominal insufflation with CO2 before induction of AP caused a significant decrease in ascites volume, cells, and TNF-alpha in the peritoneal cavity and in serum TNF-alpha and IL-6 but not IL-10 levels. In the pancreas, this treatment reduced MPO activity, acinar and fat necrosis, and the expression of inducible nitric oxide synthase and cyclo-oxygenase 2. There were no significant differences on serum amylase levels, liver mitochondrial function, and pulmonary MPO between groups.

CONCLUSIONS

Our data demonstrated that CO2 pneumoperitoneum reduced pancreatic inflammation and attenuated systemic inflammatory response in AP. This article suggests that CO2 pneumoperitoneum plays a critical role on the better outcome in patients undergoing laparoscopic pancreatic surgery.