| It's known that lipopolysaccharide (LPS) plays an important role in activating immune and inflammatory systems and causing shock and multiple organs failure (MOF) inside the human body. The harmful effects of endotoxin are due to the excessive inflammation responses induced by various kinds of endogenous cytokines, which have been secreted right after the stimulation of LPS. Moreover, in the whole process, the over activation and chemotaxis of polymorphnuclear leukocytes (PMN) is an important initial step in mediating inflammation response and tissue impairment. Thus, inhibiting the over activation and chemotaxis of PMN is an effective way to prevent inflammatory reactions advancing into infectious shock. Polydatin (PD), a kind of anti-shock drug, which was extracted from a kind of Chinese herb medicine Polygonum Cuspidatum, was found to have good effects on the infectious and hemorrhagic shocks. Recently, it has been proved that PD could reduce adhesion of leukocyte inside micro-vein and improve the microcirculation perfusion in animals with shocks, which indicated that PD might restrain the over activation and chemotaxis of PMN. In order to investigate the mechanism of PD's power against inflammation and infectious shock, we took PMN chemotaxis in vitro as a experiment model to observe the influence of PD on the chemotaxis of PMN pretreated with LPS to mimic the inflammation situation.In the lab, chemotaxis chamber method was used to measure LPS's influence on chemotaxis activity and its production of chemotactic agent in PMN. The result showed that LPS stipulation could increase PMN cell's chemotaxis activity. PD didn't change the chemotaxis activity of normal PMN obviously, but down-regulated the increase of chemotaxis activity of LPS treated PMN. Furthermore, LPS could increase the secretion of PMN chemotactic factor and up-regulate the expression of formyl peptide receptor. PD did not obviously affect the normal secretion of PMN chemotactic factor and the expression of formyl peptide receptor, but it could significantlyreduce the rise of the excretion of PMN chemotactic factor caused by LPS stipulation and up-regulate PMN formyl peptide receptor expression.With scanning electron microscope, The PD's influence on PMN's shape and ultrastructure under LPS stipulation was observed. We found that normal PMN shows a global shape with moderate folds of cell membrane and rare piling up. After being stipulated by LPS, PMN cell became larger, the folds of cell membrane reduced, multiple cells gathered into mass and board-like pseudopodium slicked out. Under high power scanning electron microscope, it could be seen that serous membranes inlayed into each other. After PD treatment, PMN's recover to global shape with less pseudopodium formation and PMN aggregation.Finally, PD's influence on F-actin's level and distribution in LPS stimulated PMN were observed. The following changes have been noticed: Under LPS stipulation, the level of PMN F-actin obviously reduces to 80±0.02%(p<0.05) of the normal. While after PD therapy, its level increases to 89±0.018%(p<0.05). In normal situation, inside PMN, F-actin mainly locates nearby cell membrane, forming a quite dense layer of framework to hold the morphology of the cell. After LPS stimulation, F-actin forms a denser skeleton layer at the edge of cell and an uneven distribution. Adding PD treatment after LPS stipulation, F-actin at cell edge becomes much less, while increases in middle obviously, which indicate that PD may inhibit LPS's effect on F-actin.Generalizing the above findings, the following conclusions could be drew:1. PD could inhibit LPS induced PMN chemotaxis change, thesecretion of PMN chemotactic agents and chemotactic factor receptor's expression, maintain PMN's. normal chemotactic activity.2. PD could inhibit LPS induced the PMN aggregation increasing,board-like pseudopodium sticking out, and mutual inlaying, maintain normal cell shape.3. PD could inhibit LPS induced the change of PMN F-actin's level and dis...
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