Obesity increases the severity of acute experimental pancreatitis in the rat

Background: Studies in patients with acute pancreatitis have shown a correl ation between obesity and serious complications or a fatal outcome. However , the mechanisms by which obesity aggravates acute pancreatitis are not kno wn. In the present study we used the sodium taurocholate model of pancreati tis to examine the effect of obesity on severity and outcome in acute exper imental pancreatitis (AEP). Methods: AEP was induced at two degrees of seve rity by retrograde infusion of sodium taurocholate (0.2 ml x 3% or 0.4 ml x 3.5%) into the pancreatic duct of rats with obesity induced by high-fat di et, genetically obese (GO) rats or lean control rats. Surviving animals wer e sacrificed 72 h after induction of pancreatitis. Results: In the low-dose experiment, there were no significant differences in pancreatic histology or survival rate between the groups. In the high-dose experiment, the GO ra ts had a significantly lower 72-h survival rate than the high-fat obese (HF O) or lean control (LC) groups (GO 25% versus HFO 73%. P < 0.05: GO 25% ver sus LC 100%, P < 0.001). Survival rates in the high-dose experiment correla ted strongly with basal liver fat content (R-2=0.86). Pancreatic histology showed significantly more fat necrosis and a higher total pathological mean score in the HFO rats than in the LC animals (both P < 0.05). Conclusions: Obesity had a negative influence on the outcome of necrotizing pancreatiti s that was related to the magnitude of the pancreatic insult. The sodium ta urocholate model in obese rats would be useful for future mechanistic studi es of the effect of obesity on pancreatitis.