Protective Effect Of Dexmedetomidine On Curing Sepsis-induced Hepatocyte Injury

Objective To explore the effect of dexmedetomidine(DEX)on prognosis of septic mice through observing the survival state and mortality rate in vivo. To investigate whether DEX has a protective effect on sepsis-associated liver injury and hepatocyte injury through observing the cultured damaged mouse liver cells and hepatocytes stimulated with LPS including the growth condition, proliferation and apoptosis rates as well as the content of albumin in the supernatant in vitro, thus providing usefully theoretical reference and some novel guidelines for the application of DEX in critically ill patients on sepsis in perioperative period.Methods 1 In vivo experiments Cecal ligation and puncture(CLP) was used to establish the model of sepsis in mice. Fifty healthy male C57BL/6 mice, weighted 19-21 g,were randomly divided into five groups. In each group, there were ten mice. The groups were as follows: control group(C group), sepsis group(CLP group), dexmedetomidine group(D1 group, 30?g/kg; D2 group, 40?g/kg; D3 group, 50?g/kg). Except C group, other groups had CLP surgery to establish model of sepsis-induced liver injury. One hour after the surgery, the mice in D1?D2?D3 group were received intraperitoneal injection with30?g/kg, 40?g/kg, 50?g/kg of DEX, while C and CLP groups were received equal volume of normal saline instead. All of mice in each group took food and water freely in experimental period. The long-term survival and mortality of mice were observed after different treatment. 2 In extro experiment Cecal ligation and puncture(CLP) was used to establish the model of sepsis-induced liver injury in mice. Another thirty healthy male C57BL/6 mice, weighted 19-21 g, were randomly divided into five groups. And there were six mice in each group. The subsequent grouping and operating were same as the experiment in vivo. Forty-eight hours after the models being set up, the blood was taken from the eyeballs of the mice for detecting the serum level of alanine aminotransferase(ALT). Then the mice were sacrificed to take out the livers. The livers were made into single cell suspension to culture it in vitro. Living cells were counted and cell concentration was adjusted to 5 × 105 cell/ ml. All groups were placed in 37? 5% CO2 saturated humidity to be cultured for 48 h. The medium was changed the next day. After culture completion the cells were collected to examining hepatocytes proliferation by cell counting and apoptosis by FACS analysis. 3 In vitro experiment The model of lipopolysaccharide( LPS)-induced hepatocyte injury was prepared. Took the NCTC 1469 cells in logarithmic growth phase and divided them into 5 groups: control group(c group),hepatocyte injury group(LPS group), dexmedetomidine group(d1?d2?d3 group). Living cells were counted and cell concentration was adjusted to 5 × 105 cell/ ml. The cells were seeded into 96-well plates and each group was established six holes. Except c group, LPS at concentration of 100?g/ml was used to induce injury to the cultured cells and 10ng/ml,100ng/ml, 1?g/ml DEX were added at the same time in d1?d2?d3 group while c group was received equal volume of normal saline instead. All groups were placed in 37? 5%CO2 saturated humidity to be cultured for 24 h. Cell culture supernatants were collected and the expressions of albumin were detected. The morphological changes of NCTC 1469 cells were recorded by inverted microscope. After culture completion the cells were collected to examining hepatocytes proliferation by cell counting and apoptosis by FACS analysis.Results 1 In vivo experiment Many symptoms of the mice in CLP group were observed including action retardation, gloomy spirit, chilly, clothing hair erection and diarrhea. No mice died in C group during the experiment, and they all developed normally with stable weight. There was no significant difference in mortality of mice between CLP group and D1 group. While the mortality rate in D2 and D3 group were lower than that in CLP group. Liver gross morphology changes: C group, normal liver morphology, capsule smooth, complete, red color, soft texture. While in the CLP group, the liver was obviously swelling and hyperemic with petechial hemorrages and punctiform areas. 2 In extro experiment Apoptosis rate and the expression of ALT in DEX group were not only lower than CLP group( P<0.05), but also higher than C group with a dose response relationship.The proliferation rate was significantly higher than that in CLP group(P<0.05). 3 In vitro experiment The cultured NCTC1469 cells in LPS group were seriously damaged and the apoptosis rate was increased compared with group c(P<0.05). In dex groups, the state of cultured cells were improved, albumin contents and cell proliferation rate were significantly increased(P<0.05).Conclusions 1 Dexmedetomidine can significantly improve the survival state and survival rate of septic mice in a dose-dependent manner. 2 Dexmedetomidine can effectively improve the sepsis-associated liver injury by inhibiting apoptosis and promoting cell proliferation. 3 High dose of LPS can cause serious injury of liver cells,increase cell apoptosis, inhibit cell proliferation and reduce the liver cell function.Dexmedetomidine can effectively improve the LPS-induced hepatocyte injury by inhibiting apoptosis and promoting cell proliferation.