The Effect Of Dexmedetomidine, Midazolam And Propofol On The Lipopolysaccharide-stimulated Dendritic Cells

Background:Dexmedetomidine, midazolam and propofol, are the common sedative drugs in Intensive Care Unit (ICU), which widely used by patients who accept tracheal intubation, and many of them have sepsis or sepsis shock. Recently, the effects of these sedative drugs on inflammation have been taken seriously.Dendritic cells (DCs) are the most crucial type of cells in immunity and inflammation, with the capacity of specialized antigen-processing and presenting. Lipopolysaccharide (LPS), a bacterial endotoxin contributed to sepsis, can stimulate DCs and induced to the inflammation response which may stimulate the expression of inflammation cytokine, such as TNF-α, IL-1β, IL-6and IL-10. Meanwhile, the overproduction of cyclooxygenase-2(COX2) enzymes with ability of aggravating inflammation, could be enhanced by LPS. In the inflammation response, nuclear factor kappaB (NF-kB) and mitogen-activated protein kinase (MAPK) pathway play a vital role.Previous studies have shown midazolam and propofol had anti-inflammatory properties in a variety of experimental models. Dexmedetomidine, a highly selective agonist of the a2adrenergic receptors and a relative new sedative, may play biphasic effect on the cells and show its antiflammation in vivo. But most vitro studies concentrated on the effect in macrophage or microglia, and few involved in DCs. Therefore, we designed the current experiment to illustrate the effects of dexmedetomidine, midazolam and propofol with different doses based on the clinical blood concentration on the production of inflammation mediators in LPS-activated DCs, and then we attempt to explore their possible mechanism.Purpose:We designed the current experiment to illustrate the effects of dexmedetomidine, midazolam and propofol with different doses based on the clinical blood concentration on the production of inflammation mediators in LPS-activated dendritic cells, and then we attempt to explore their possible mechanism.Method:(1). Cells were treated with the indicated concentration of dexmedetomidine (1,0.1,0.01,0.001uM), midazolam (50,10,1,0.1uM), or propofol (100,50,15,1uM) with or without LPS (1ug/ml) for24h. Then Cell Counting Kit-8was used for the assessment of cell viability.(2). Co-treatment LPS or not with dexmedetomidine (1,0.1,0.01, O.OOluM), midazolam (50,10,1,0.1uM), or propofol (100,50,15, luM) to dendritic cells for2h. The mRNA concentration of TNF-α, IL-1β, IL-6and IL-10in DC2.4cells were assayed with the PCR method.(3). Co-treatment LPS or not with dexmedetomidine (1,0.1,0.01, O.OOluM), midazolam (50,10,1,0.1uM), or propofol (100,50,15,1uM) to dendritic cells for18h. The protein concentration of TNF-α, IL-1β, IL-6and IL-10in the culture medium of DC2.4cells were assayed with the ELIS A method.(4). Co-treatment LPS (1ug/ml) or not with dexmedetomidine (1,0.1,0.01, O.OOluM), midazolam (50,10,1,0.1uM), or propofol (100,50,15,1uM) to dendritic cells for the indicated time. Western blotting to assess the expression of COX2, phospho-IkB-a, IkB-a, phospho-ERK, ERK, phospho-p38, p38, phospho-JNK and GAPDH in DC2.4. The treatment time for COX2was10h, and15min for others.Results:(1). Co-treatment LPS (lug/ml) or not with dexmedetomidine, midazolam, or propofol at the studied concentration could not alter the viability of DCs.(2). After LPS stimulated, dexmetomidine could inhibit IL-1b and IL-6at lowest concentration, but beyond that, dexmedetomidine didn’t influence cytokines significantly though NF-Kb, ERK-MAPK and JNK-MAPK were enhanced.Meanwhile, dexmedetomidine at low concentration can inhibit the JNK-MAPK pathway.(3). Cotreatment with LPS, midazolam dosages-dependently inhibited the expression of cytokines, COX2and p-JNK and enhanced the expression of IkB-a protein.(4). Propofol could inhibit pro-inflammation cytokines and inhibit p-JNK protein but enhance NF-kB and ERK at low concentration.Conclusion:After stimulated dendritic cells with LPS, the aimed sedatives played different role in inflammation, and the mechanism was different. Midazolam could obviously inhibit inflammation due to NF-kb and JNK pathway suppression. Dexmedetomidine has biphasic effect that inflammation promotion at high clinical concentration and inflammation suppression at the lowest clinical concentration (0.001uM), which attached to NF-Kb and JNK MAPK. Propofol partly inhibited pro-inflammation cytokines because of inhibition on JNK MAPK, but meanwhile, ERK and NF-kb pathway could be enhanced.