Effect Of Glucocorticoid And Growth Hormone On The Apoptosis Of Polymorphonuclear Neutrophils Injuried By Lipopolysaccharide

Objective: Sepsis and septic shock is a leading cause of morbidity and mortality in ICU, especially in children and infants.Traditionary treatment strategies can not improve the prognosis and decrease mortality. It has been identified that the apoptosis of PMNs delay in sepsis. Moreover, it is a cause of sepsis aggravation.The investigation show that glucocorticoid can inhibit the apoptosis of PMNs.We review the effect of the glucocorticoid on the apoptosis of PMNs injuried by LPS in our experiment.In addition, growth hormone has been used in severe disease.The effect of growth hormone on PMNs apoptosis in the sepsis is anothor experimental destination.Methods: Separate PMNs from blood in healthy human with a discontinuous denisity-gradient centrifugation.PMNs were cultured in enriched RPMI 1640 media at 2×10⁶/ml for 24 hours(37℃, 5%CO₂).There are eigtht groups in the experiment: normal control group (N), lipopolysaccharide group (LPS),high dose dexamethasone group (DEX1), low dose dexamethasone group (DEX2), treatment byhigh dose dexamethasone group (LPS+DEX1) , treatment by low dose dexamethasone group (LPS+DEX2) ,growth hormone group (GH) , treatment by growth hormone group (LPS+GH ) .The final concentration of LPS, DEX1, DEX2 and GH is lOug/ml, 10'6M,10"8M and lOOug/ml.PMNs apoptosis were assessed by Annexin-V FITC staining using flow-cytometry at three hours,six hours,twelve hours and twenty-four hours after culturing in different groups.Results: The apoptosis rate of PMNs decrease after culturing with LPS (P<0.01).The apoptosis rate of PMNs is lower than the normal control when culturing with different dose dexamethasone in three hours, six hours and twelve hours (P<0.05).The apoptosis rate is still low after culturing twenty-four hours, but it is no differences (P>0.05).There are no significant differences in apoptosis rate between high dose and low dose dexamethasone (P>0.05). When culturing with LPS, high dose or low dose dexamethasone in three ,six and twelve hours, the apoptosis rate of PMNs is higher than LPS group (P<0.01). After twenty-four hours ,dexamethasone can not improve the apoptosis rate of PMNs injured by LPS(P>0.05).There are no differences in apoptosis rate between different dexamethasone groups(P>0.05).The apoptosis rate of PMNs is not different after culturing with GH in six and twelve hours(P>0.05).When culturing with LPS in six and twelve hours,the apoptosis rate of PMNs is higher than LPS group(P<0.05).After twelve hours,the rate not only is higer than LPS but also approaches to normal group(P>0.05).