The Model Of Rats With Acute Pancreatitis And Empirical Study Of Different Pressures Hyperbaric Oxygen Therapy Effects In It

Severe acute pancreatitis is one of the most difficult clinical diseases to treat, which has a high incidence and poor prognosis,with the mortality up to 30% -40%. Clinical precipitating reasons include biliary tract diseases, hyperlipidemia, diet, metabolic disorders, while in China pancreatitis mainly induced by biliary orgin. Treatment advances from surgery originally to conservative measures with selective operations, often requires multidisciplinary cooperations. The pathogenesis of acute pancreatitis, despite considerable progress has been made in recent years, was proposed as "theory of trypsin auto-digestion, microcirculation disturbance" and et al. The new therapies is on exploration, but the clinical effect is still not satisfactory. Presently it was postulated that monocyte macrophages, neutrophils , pancreatic acinar cells and other cytokines produced by activated inflammatory response syndrome which led to the occurrence of acute pancreatitis, increased the injury of body organs especially lung, liver, kidney and other vital organs. Multiple organ dysfunction (multiple organ dysfunction syndrome, MODS) or failure (multiple organ failure, MOF) that ensued profoundly affectted the prognosis of severe acute pancreatitis(SAP). So if models of acute pancreatitis can be successfully replicated, further research the value of inflammatory mediators and cytokines on the pathogenesis of pancreatitis will have a major clinical significance.Models of acute pancreatitis should have the following characteristics: it is relatively simple and reproducible, the severity of pancreatitis can be controlled, and there is much similarity between human pancreatitis and laboratory models in spite of pathological processes or morphological changes. During the early stage of SAP, fluids leakage exists, leading to lack of effective circulating volume followed by pancreatic blood supply decrease. Pancreatic necrosis resulted from ischemia and hypoxia of pancrea. Complications such as severe abdominal distension, acute respiratory distress syndrome appeared. MODS or MOF would be resulted from tissue hypoxia. This clinical problem may be solved by Hyperbaric Oxygen Therapy through raising the partial percentage of oxgen in the tissue. In this study, pancreatitis modelled by ligation of pancreatic duct, mimic the pathophysiological process of gallstone pancreatitis. HBO was used at different gradient. Results demonstrates that HBO is a promising intervention for pancreatitis therapy.Objective:To establish a model of rat with acute pancreatitis and investigate the effects of different pressures hyperbaric oxygen(HBO) therapy in it.Methods:48 adult female SD rats weighed 200-250g.48 rats were randomly divided into 3 groups :the sham operation group (n=8), control group (n=16) and HBO therapy group (n=24), then the control group were divided into 2 subgroups of 8 rats ,the HBO therapy group were divided into 3 subgroups of 8 rats. the pancreatic duct ligation in rat has become model for experimental actue pancreatitis.then,different pressures HBO therapy were implemented,each undergoing euthanasia on seventh day after the acute pancreatitis induction. Euthanasia was carried in one subgroup of control group on 1st day after operation. The pathologic changes of pancreatic tissues were observed by optic microscopy and transmission electron microscopy, the concentration of inflammatory cytokines (IL-2, IL-6, IL-10, TNF-a) of the blood were measured by ELISA. Results:Amylase level in the sham operation group after ligation is:798.50±113.5IU/L and in the control group:3156.2±639.9IU/L, there is significantly difference between the sham operation group and the control group.Each group of HBO therapy after 7days,the concentrations of inflammatory cytokines (IL-2, IL-6, IL-10, TNF-a) in HBO therapy group and control group was a significant difference( P=0.000,P<0.05 ) . The concentrations of IL-2, IL-6, IL-10 in different pressures HBO therapy group were significant difference(P<0.05). The concentrations of TNF-a in 0.15-0.20Mpa group and 0.15-0.25Mpa group was significant difference(P=0.019,P=0.000,P<0.05).There was no significant difference in 0.20-0.25Mpa group(P=0.085,P>0.05).There were significant improvement in pancreatic tissue which has been observed by histology.Conclusions:HBO therapy with 0.15-0.20 Mpa or 0.25 Mpa is safe and effective for actue pancreatitis. The concentrations of inflammatory cytokines decreases with the increasing HBO pressure in rat with acute pancreatitis.