etc Effect of Butyrate on the Activation of NF B in Lung Tissues of Mice with ALI After LPS administration, the expression of NF B p65 in nucleus markedly increased and peaked at 3 hours. The expression of NF B p65 in nucleus induced by LPS was significantly suppressed at 1, 3 and 6 hours by butyrate pretreatment. On the contrary, the expression of NF B p65 in cytoplasm was significantly reduced by LPS administra tion, and these changes were inhibited by butyrate pretreatment. No changes increased the release of the pro inflammatory cytokine IL 8 in human alveolar epithelial cells treated by TNF a. Moreover, TSA enhanced IL 8 production in SV 40 transformed lung epithelial cells stimulated by LPS. Based on the results observed in lung epithelial cells, HDAC inhibitors seemed to be pro inflammatory in ALI.
In the present study, interestingly, our results indi cated that administration of butyrate in vivo attenuated pulmonary inflammation in LPS induced ALI. The rea son for the discrepancy may be related to the different circumstances in vitro and in vivo. Furthermore, although the alveolar epithelial cells are the main part of lung tissues, the alveolar macrophages and neutrophils play a central role in ALI but not alveolar epithelial cells, which may contribute to the discrepancy. Consis tent with the present study, TSA attenuated the devel opment of allergic airway inflammation by decreasing expression of the Th2 cytokines, IL 4 and IL 5, reduced spinal cord inflammation, demyelination, neuronal and axonal loss, and ameliorated disability in the relapsing phase of experimental autoimmune encephalomyelitis, a model of multiple sclerosis.
Therefore, different from the variable results observed in vitro, HDAC inhi bitors are more likely to exert their anti inflammatory effects in vivo. NF B pathway has been considered to play a pivotal role in the pathogenesis of ALI. NF B is normally retained in the cytoplasm in an inactive form through being associated with an inhibitor of B protein. NF B is activated by a variety of pathogens known to cause inflammation and sepsis, including LPS. Following activation, the I B protein breaks down and liberates NF B to enter Entinostat the nucleus where it binds to specific sequences in the promoter enhancer regions of genes. Thus, NF B improves the transcription of most pro inflammatory molecules, including adhesion molecules, enzymes, cytokines, and chemokines. Among these pro inflammatory molecules, TNF a and IL 1b are the most important cytokines in the pathogenesis of ALI. Elevated concentrations of TNF a and IL 1b have been measured in BALF from patients with ARDS, and were related to prognosis.