Study On The Expression Of L-selectin At Transcription And Translation Level In Hemorrhagic Shock Rat

Leukocyte-endothelium adhesion (LEA) and capillary plugging is one of the reasons of reduction of microcirculation flowing in shock.The moving of leukcytes out of capillary include 4 steps:rolling,adherence,transmigration and chemotaxis.The selectin families which is one of cell adhesion molecules (CAMs) mediate the first step.The selectin families have three hinds:P-selectin ,L-selectin and E-selectin.The L-selectin is thought to be important in the rapid rolling of leukocyte along the endothelium.We observe the dynamic expression changes of L-selectin at levels of transcription and translation in hemorrhagic shock rat in this study.The aims of present study is to investigate the role of L-selectin in pathophysiological procedure of hemorrhagic shock.. Materials and Methods 24 rats (male,weight 300-360g)are classified 3 groups.The 8 rats their blood samples withdrawn by cutting tails are set as normal group;the 8 carotid puncture rats are set as control group;hemorrhagic shock model is produced in 8 rats .The surface expression of L-selectin in neutrophils is detected and analyzed by flow cytometry and mRNA is detected by reverse transcription polymerase chain reaction (RT-PCR).Measurements are taken at control group,hemorrhagic shock group and matching times of normal group of pre,O,1,2,3,4,5h.Data are expressed as mean?SD.Statistical analysis was by ANO VA. 4 Results These data show that there are definable and quantifiable kinetics changes in leukocyte after trauma and shock in rats.Neutrophil L-selectin expression in tail-cut rats showed no significant change (p>0. 05) in corresponding times.The surface expression and mRNA are up regulated of controls compared with normal group(p<0. 05). The peak values of surface expression is at 3 hour and last 4? hour while the peak values of mRNA is at 5 hour after injury. The values above of hemorrhagic shock group are early up regulated compared with normal group (pKO. 05) while late down regulated after 3 hour compared with controls(p<0. 05). Conclusion 1 The tail-cut rats can be set as normal group. 2 The carotid puncture operation is a moderate-major trauma for rats accompanied by increasing expression of L-selectin.This result indicate that a trauma control group must be set in this hemorrhagic shock model. 3 In the hemorrhagic shock rats, the L-selectin is down-regulated.This result may be associated with alleviation effects of the excessive adhesion reaction and may improve microcirculation 4 The surface expression of L-selectin may depent on the synthesizing of mRNA. The immediate increasing expression of cell surface in this study is likely due to the direct releasing of L-selectin from cytoplasm and shedding from cell surface. 5 The up-regulation after trauma may promote the adhesion of leucocytes to the venule wall and the inflammatory response,and may be bertificial to healing of wound and enhance the ability of anti-infection.