| Background: Sepsis is a systemic immune response syndrome caused by infection(SIRS).It is a disease that multi-organs and multiple systems dysfunction caused by unguided inflammatory response.The myocardial dysfunction caused by sepsis,with 50% morbidity rate,bring death and poor prognosis,is one of the major complication.Exogenous glucocorticoid may reverse sepsis myocardial injury in serious condition.However,the inevitable complications companying with high-dosage glucocorticoid therapy are very hard to treat,such as gastrointestinal bleeding,infection aggravation etc.So the development of new anti-endotoxin drug with the characteristic of high-efficient and low toxicity is necessary,for the purpose of replacing corticosteroid,decreasing the side effects.Ginseng is a traditional Chinese medicine.Ginseng extract has excellent effect of improving cardiac function,protecting myocardial cells to resist injury and apoptosis.The panaxadiol saponins(PDS),a kind of small molecular fat-soluble drug with much lower toxicity.The prophase research of our team found that PDS can improve the cardiopulmonary function of uncontrolled hemorrhagic shock dogs,and the renal damage induced by sepsis.PDS extract excellent treatment effect to the function and structure of the viscera and cells.So a futher research of panaxadiol saponins(PDS)is indispensable.Purpose: By peritoneal injection of LPS in mice,simulats myocardial injury during the spesis.Contrastive research the effect of PDS and dexamethasone in improving the myocardial injury induced by LPS in mice.Investigate its Anti-inflammatory,anti-apoptotic and anti-oxidative stress impact of protecting cardiac.Thus providing basic research data for its alternative possibility of taking the place of dexamethasone hormone drugs treating myocardial injury induced by LPS.Methods and Results: 1.Establish acute myocardial injury model induced by LPS in mice The male C57 BL / 6 mice were randomly divided into four groups(n = 8): the control group,LPS group,LPS + PDS group and LPS + DEX group.The control group mice was injected intraperitoneally 0.5 ml PBS buffer,The mice in LPS + PDS was injected intraperitoneally PDS(25 mg/kg),The LPS + DEX group was injected intraperitoneally dexamethasone(2.5 mg/kg);One hour later,The mice in LPS group,LPS + PDS group and LPS + DEX group was injected intraperitoneally LPS(10 mg/kg).Seven hours later,anaesthetized mice was detected the cardiac function by echocardiography.After the test,the mice was killed after nine hours of LPS injection.Collecting blood and cardiac tissues in order to used in the futher detection.The ultrasonic echocardiography results showed that the Ejection fraction(EF)and Shortening fraction(FS)declined significantly in LPS group mice compared with the control group(P<0.01).The thickness of left ventricular posterior wall,left ventricular cavity and interventricular septum were increased(P<0.01).On the other hand,HE staining of mice in LPS group has displayed the inflammatory cell infiltration around the cardiomyocytes,muscle fiber deformation.All of the phenomenon indicates that the model was set up successfully.2.PDS can protect cardiac function in mice with acute myocardial injury induced by LPS,which dexamethasone has a similar effection.Compared with LPS group,many cardiac index in ultrasonic echocardiography of LPS+PDS group was improved,EF and FS were getted right,left ventricular morphology was restored.LPS+DEX group has a similar results.Detecting myocardial injury markers in mice,LDH and CK,we found that the myocardial inflammatory injury induced by LPS significantly increased the level of LDH and CK(P<0.01).While after treated with PDS and DEX,the above indicators decreased.It is inferred that PDS and DEX will improve the myocardial injury in mice caused by LPS,have therapeutic effect.3.PDS will reduce the level of TNF-α and IL-6 in the serum and myocardial tissue of acute myocardial injury caused by LPS.The standard of TNF-α and IL-6 in serum were detected by the kit.According to the results,the standard of TNF-α and IL-6 of LPS group in serum has a significantly higher level compared with the control group(P<0.05),which prompts a large number of inflammatory factors enter into blood in the effect of LPS.However,compared with LPS group,the content of TNF-α and IL-6 in the LPS + PDS group was significantly reduced(P < 0.05),The content of TNF-α in LPS+DEX group appeared a downward trend in contrast with LPS group,but no statistical significance.While the content of IL-6 was significantly reduced(P<0.05).The detection of myocardial tissue in mice showed that,there is no differences between groups about the IL-6 m RNA in mice heart tissue.While the levels of TNF-α m RNA was pronounced increased in LPS group(P<0.05),nevertheless was reduced in PDS and DEX treated group(P<0.05).The results prompts that it will be the positive achievements of PDS and DEX in inhibiting the inflammatory related pathways,protecting heat tissues.4.PDS will reduce the myocardial cell apoptosis of mice in acute myocardial injury caused by LPS Using Western Blot to detect the expression of apoptosis related proteins in heart tissue.The results showed that the expression of pro-apoptotic protein Cleaved PARP,Cleaved caspase3 and Bax increased significantly in LPS group compared with control group(P<0.05),cytochrome C presented a increasing trend.The Bcl-2,Anti-apoptotic proteins,appeared to decreased significantly(P<0.05).Compared with LPS group,the expression of Cleaved PARP,Cleaved caspase3,Bax and cytochrome C in LPS + PDS group decreased significantly(P<0.05);the expression of Cleaved PARP,Cleaved caspase3 in LPS+DEX group were reduced significantly(P<0.05),Bax and Cyto C had a decreasing tendency.Thus the PDS and DEX will impact the expression of apoptosis related proteins,reduce the myocardial apoptosis caused by LPS,protect the myocardial tissue.5.PDS will suppress the activation of NF-κB signaling pathway in acute myocardial injury caused by LPS Results of western blot showed that the phosphorylation IκB alpha(p-IκBα)was significantly increased(P < 0.05),The ratio of p-IκBα/t-IκBα was markedly increased(P < 0.01).When given a PDS and DEX management,the ratio of p-IκBα/t-IκBα would be significantly decreased(P < 0.01).The Extraction of cells’ nucleus protein in myocardial let us dicovered that compared with control group,nucleus protein NF-κB p50 and p65 in LPS group were significantly increased(P < 0.05).When given a PDS and DEX treatment,The expression of NF-κB p50 and p65 were obviously decreased(P < 0.05).In conclusion,PDS and DEX will suppress NF-κB signaling pathways,The p50 and p65 proteins nuclear importing are decreased,reverse the mouse myocardial injury induced by LPS.6.PDS will reduce the level of oxidative stress in acute myocardial injury mice caused by LPS.Tested the NAD + / NADH in the four groups of mice in myocardial tissue.We found that the ratio in LPS group was obviously higher than that of control group(P < 0.01).This suggests that NAD + / NADH homeostasis is damaged and oxidative injury aggravated in acute myocardial injury caused by LPS.The level of MDA in the myocardial tissue was also increased significantly(P < 0.05),and the expression of SOD decreased(P < 0.05).After the treatment of PDS and DEX,the ratio had a down regulation(P < 0.05),the level of MDA was also decreased,SOD has a restoration tendency(P < 0.05).The results illustrates that reducing cells’ oxidative damage may be one of the mechanisms of PDS resists myocardial damage caused by LPS.Conclusion: 1.PDS will improve the mice’s systolic function of heart in acute myocardial injury induced by LPS,suppress production and release of inflammatory cytokines,reduce the apoptosis and oxidative stress of myocardial cells.2.The mechanism of PDS improving acute myocardial injury caused by LPS is related to the inhibition of NF-κB signaling pathway activation. |
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