Effect Of Scopolamine Pretreatment On The Microcirculation And Lung Injury In Septic Shock Rats

Part 1 Comparison of Two Different Models of Sepsis Induced by Cecal Ligation and Puncture in RatsObjective The present study was designed to explore the difference between two rat models of sepsis and to establish a more stable rat model.Methods Sprague-Dawley rats were randomly divided into three groups: Sham operation group(Sham),simply cecal ligation and puncture group(SCLP),and cecal ligation perforation plus drainage strip group(CLP-DS).The general condition of rats were observed,and the time of death and the survival rate of72 h were recorded,and the changes in abdominal cavity were observed 24 h after modeling.Six rats were randomly selected from each group,the abdominal aorta blood and lung tissues were obtained 9h after modeling,peripheral blood interleukin-6(IL-6)、tumor necrosis factor alpha(TNF-α)level were detected by enzyme-linked immunosorbent assay(ELISA),and pathological section of lung tissue and Smith score were observed.Results The 72-hour mortality of CLP-DS group were significantly higher than that of SCLP group(P<0.01),no death cases was found in the sham operation group.The limitation package,intestinal adhesion,and poor drainage were detected in the SCLP rats,whereas intestinal edema and hyperemia,bloody water in the abdominal cavity,but no inflammatory package were observed 24 h after the operation in the CLP-DS rats by autopsy.There were significant differences in IL-6 levels and TNF-alpha levels between the SCLP group and the CLP-DS group(all P<0.01),and the concentrations of inflammatory mediators in the two groups were higher than those in the sham operation group.Thin alveolar wall with no obvious inflammatory cell infiltration in the Sham group,severe pulmonary septal thickening,alveolar wall vascular congestion,and protein debris deposition in the alveolar cavity were observed in the SCLP group,whereas pulmonary bullae were observed in the CLP-DS group using the light microscopy,and there were significant difference among groups in Smith lung injury score.Conclusions These results suggested that the cecal ligation combined with puncture drainage model of sepsis is more stable than that of the simple cecal ligation and puncture model of sepsis in the rat,which resolved the problem of puncture wrapped in the traditional CLP model of sepsis in rats.Part 2 Effect of scopolamine pretreatment on the microcirculation and lung injury in septic shock ratsObjective Scopolamine may block the further accumulation and release of inflammatory cells and inflammatory mediators,and effectively relieve the spasm of vascular smooth muscle.This study investigated whether scopolamine pretreatment could relieve microcirculation dysfunction and reduce lung injury in septic shock rats.Methods1.Grouping: A total of 48 SD rats were randomly divided into four groups(weight 250~300g): Sham group,Control group,Saline group,Scopolamine group;2.Preoperative monitoring: The values of the arterial blood flow pattern,arterial blood flow velocity,mean internal arteriolar diameter,mean internal venular diameter and the internal major cycle are the basis values.3.Operation: The sham group only underwent laparotomy and abdominal operation,cecal ligation combined with puncture-drainage strip(CLP-DS)was operated in the other groups;4.Observation: The microcirculation indexes of the terminal ileum were measured by BI2000 dynamic microcirculation image acquisition and analysis system,and the variation ratio from pre-operation to post-operation was calculated;The concentrations of inflammatory factors(IL-6,TNF-α,IL-10)in serum of rats were detected by enzyme linked–immunosorbent assay(ELISA).Measurement wet to dry ratio of lung and pathological section of lung tissue were observed.Results(1)Changes of microcirculation indexes: I Changes of arterial blood flow patterns in rats of each group,the Sham group showed better than the other groups,compared with Control group and Saline group,the arterial blood flow pattern of Scopolamine group was better;II The variation ratio of arterial blood flow velocity from pre-operation to post-operation,were significant differences among groups(P(27)0.01);III Variation ratio of mean internal arteriolar diameter from pre-operation to post-operation,was significant difference among groups(P<0.05);IV Variation ratio of mean internal venular diameter from pre-operation to post-operation: compared with Scop group,the Saline group has significant difference in statistics among groups(P<0.05).(2)Change of internal main cycle: the major cycle of rats in each group changed slight.(3) Levels of inflammatory factors in serum: The concentrations of inflammatory factors in Scop group were lower than those in Control group and Saline group,but all groups were higher than those in Sham group;In addition to Control group compared with Scop group had significant difference in TNF-alpha of serum(P(27)0.05),the other concentrations of inflammatory factors in Control group and Saline group compared with Scop group were statistically significant(P<0.05),the difference between the Saline group and Control group had no statistical significance(P(29)0.05).(4)Wet to dry of lung(W/D): the Saline group was higher than the other groups,there was significant differences in statistics(P<0.05),but the other groups were not statistically significant among two groups(P>0.05).(5)Light microscopy shows that thin alveolar wall,no obvious inflammatory cell infiltration,no thickening of pulmonary septum and hyperemia were observed in the lung tissue of Sham group.Pulmonary septal thickening and congestion,bulla formation,severe alveolar septal rupture,and a large number of inflammatory cell infiltration and aggregation were observed in the lung tissue of Control group.Partial pulmonary septal rupture and edema formation,and a large number of inflammatory cell infiltration and aggregation were observed in the lung tissue of Saline group.Some pulmonary septal rupture and atelectasis,and a small amount of inflammatory cell infiltration and aggregation were observed in the lung tissue of Scop group.Conclusions Scopolamine pretreatment can improve micro-arterial blood flow and increase mean arterioles diameter and venule diameter on the basis of fluid resuscitation in septic shock rats,and could reduce the level of inflammatory factors in the blood circulation and relieve pulmonary injury.