Effects Of Simvastatin Pretreatment On Coagulation Function And C-reactive Protein Of Liver In Septic Rats

Objective: Sepsis is a complex clinical syndrome which brings about organ function damage due to interactions among pathogen infection,and host immune system,inflammatory reaction,and coagulation response.It is the primary cause of critically patients'death. The main pathophysiological mechanism of sepsis is the simultaneous initiation of inflammatory reaction and coagulation cascade response. Excessive inflammatory reaction and cascade effect which is out of control will result in ultimate organ dysfunction or even death. Coagulation disorder which is extraordinary common in sepsis includes procoagulant activity increasing, anticoagulant activity weakening and fibrinolysis system inhibited. Excessive activating in coagulation system will cause blood clotting factor consumption and bleeding tendency. As a result,disseminated intravascular coagulation will happen. The formation of microthrombus in capillary vessels is one of the important characteristics of sepsis. In recent years, it has been found in several foreign researches that statins could protect the endothelial function effectively. It has the functions of anti-inflammatory, anticoagulation, reducing damage to vital organs and diminishing mortality. The application of statins provides a new method for the treatment of sepsis. In this experiment, we established the rat model of sepsis induced by cecal ligation and puncture to observe the effects of simvastatin pretreatment on coagulation function and C-reactive protein of liver in septic rats.We recognized the pathophysiological occurrence and development of sepsis and protection mechanism of statins through multiple observation time points,in order to apply a new interference to sepsis treatment,decrease complications and reduce the mortality.Methods:Eighty clean healthy female Wistar rats with weight 200~250g were chosen and divided into four groups at random: groupⅠ:nomal group(n=8):killed the rats after anesthesia,groupⅡ:sham group(n=24):only open the abdominal cavity without CLP,groupⅢ:sepsis model group (n=24): undertake CLP,groupⅣ:prevention group (n=24):injected 20mg.kg-1.day-1 simvastatin(1ml sterile water for injection) to their stomaches for two weeks before CLP .The remains groups injected equal saline to the stomaches in the same way. Each group killed eight rats effectively at 6h,24h,48h point and collected blood samples and liver tissue specimens.Monitor and record the general situation of rats in each group,such as the coat,the state of mind,rectal temperature,survival rate and so on. Apply the completely automatic blood analyzer to examine white blood cell and the platelet count in each group.At the same time,we observed the changes of TF and PAI-1 in serum and the level of CRP in liver tissue in each group.Data were analyzed using SPSS 12.0 statistcal program. Differences in measurement data which were presented as x?±s were compared with One way ANOVA.Enumeration data were analyzed using Fisher's exact test. A level of P<0.05 was considered to be statistically significant.Results:1 General situationThe rats in nomal group could have normal activity, respiration rate, defecation and sensitive response.Their coat was smooth and glossy. There were no offensive odour,bloody ascites and intestinal flatulence when the abdomen was opened.All the rats in nomal group were alive. Rats in sham group were awake completely after CLP 1 hours. Their rectal temperature had gone back to normal little by little. General situation such as drinking freely,was the same as normal group.No rats in this group were died. Rats in CLP group were awake completely after CLP 1.5 hours.They were depressed with inaction,piloerection,faster respiration rate,lower rectal temperature, drinking little water freely,slower response to stimulate,obvious abdominal distention,watery feces.When the abdomen was opened we could smelled offensive odour.The cecums were darken,on the surface of which had some pus.There were intestinal flatulence and bloody ascites in the abdominal cavity.On the surface of liver appeared lots of petechiae.The number of survival rats in simvastatin prevention group was more than that in CLP group at each time points.In this group,activity and clinical manifestations of rats survivaled were better than those in CLP group.2 Survival rateThe survival rate of normal group and sham group in 48 hours , CLP group and prevention group in 6 hours was 100%. Survival rate gradually lower with the prolongation of time. Survival rate in prevention group in 24 hours,48 hours was higher than that in CLP group,however,there were not statistically significant difference between CLP group and prevention group for the survival rate (P﹥0.05).3WBCThe mean of WBC in CLP group decrease by 50% compared with sham group at 6h,24h,48h point,according with standard of diagnosis of animal SIRS.4 Rectal temperatureRectal temperature in CLP group descend more than 1℃compared with sham group at 6h,24h,48h point,according with standard of diagnosis of animal SIRS.5 TFThe lever of TF in sham group has no significant difference compared with that in normal group at each time (P﹥0.05).The level of TF in CLP group was significantly increased compared with that in sham group at 6h,24h,48h point after CLP(P﹤0.01),The level of TF in serum obviously increased at 6h,reached the peak at 24h and decreased at 48h to some extent.The level of TF of serum in prevention group was lower than that in CLP group at 6h,24h,48h point after CLP(180.45±61.20 vs 312.15±83.54,341.63±53.52 vs 448.18±54.19,203.13±52.64 vs 310.37±39.75, P﹤0.01).6 PAI-1The lever of PAI-1 in sham group has no significant difference compared with that in normal group at each time (P﹥0.05).The level of PAI-1 in CLP group was significantly increased compared with that in sham group at 6h,24h,48h point after CLP(P﹤0.01),The level of TF in serum markedly increased at 6h,reached the peak at 24h and decreased at 48h to some extent.The level of PAI-1 of serum in prevention group was significantly decreased compared with that in CLP group at 6h,24h,48h point after CLP(2.08±0.31 vs 2.71±0.39,2.06±0.37 vs 3.42±0.58,1.75±0.24 vs 2.32±0.25,P﹤0.01).7 PLTThe lever of PLT in sham group has no significant difference compared with that in normal group at each time (P﹥0.05) . The lever of PLT in CLP group was lower than that of sham group at 6h,24h,48h point after CLP (P﹤0.01) .With the prolongation of time, the level of PLT declined by degrees.The level of PLT in prevention group was significantly increased compared with that in CLP group at 6h,24h,48h point after CLP(629.33±31.94 vs 524.00±65.74,571.67±22.01 vs 514.33±32.32,546.00±34.04 vs 452.00±32.00,P﹤0.01).8 CRP in liver tissueExpression of CRP in liver was mainly in plasma. Positive cells were brown.The level of CRP in sham group has no significant difference compared with that in normal group at each time(P>0.5).Hepatocytes of hepatic lobule were arrayed in order. There were a few positive cells in sham group. The CRP positive cell ratio in CLP group was obviously higher than that of sham group at each time point (P﹤0.01). The CRP positive cell ratio of CLP group at 24h was more than that at 6h,48h point.Hepatocytes of hepatic lobule were arrayed disorderly.The level of CRP positive cells in prevention group were decreased compared with that in CLP group at each time point(15.00±3.00 vs 27.67±2.52,11.67±3.51 vs 24.00±8.19,18.00±3.00 vs 26.00±5.57,P﹤0.01). Hepatocytes of hepatic lobule were arrayed in order.Conclusions:1 A septic model can be made successfully by cecal ligation and puncture. 2 Sepsis induced by cecal ligation and puncture could increase the lever of tissue factor and plasminogen activator inhibitor-1 in the serum , decrease platelet count.3 Pretreatment with simvastatin could inhibit the production of tissue factor and plasminogen activator inhibitor-1 in the serum,decrease consumption of platelets.4 Pretreatment with simvastatin could descend the lever of C-reactive protein of liver,alleviate the degree of liver inflammation and protect liver function.