And TLR4 in vivo and vitro study. In the aspects of cardiac echocardiography, there are discrepancies between the parameters of LV function in the present study. We consider that the discrepancies would be made 1317923 because of the methodological limitations of echocardiography in rats. ICV injection of SC-1 TLR4-SiRNA improves LV dP/dt and LVEDP, not infarct size and LV fractional shortening. We consider that infarct size and LV fractional shortening are varied data, and the benefits on LV dP/dt and LVEDP are meaningful to a greater extent than infarct size and LV fractional shortening. Moreover, we demonstrated that ICV injection of TLR4-SiRNA improves LVEF and cardiac output. Taking all, we consider that ICV injection of TLR4-SiRNA could improve LV performance in MI-induced heart failure. There are several limitations in the present study. First and the most important limitation is that we could not do the really “silencing” of TLR4 in brainstem by ICV injection of TLR4SiRNA in the present study. Although we tried to do the silencing of TLR4 by TLR4-SiRNA in higher doses, the expression of TLR4 in brainstem could not really silenced (data not shown). Because the aim of the present study was to decrease TLR4 in brainstem, we accepted ICV injection of TLR4-SiRNA. However, it is not really “silencing”. Second, we did not identify the area in the brain where the activation of TLR4 is occurred, and we also did not do the cite-specific silencing TLR4 for a longer period,especially at 1315463 the nucleus involved in the cardiovascular regulation. Because of these limitations, we could not determine the benefits of silencing brain TLR4 on the survival. To clarify these issues, we should do really silencing brain TLR4 for several months by other methods in a future. Finally, we still did not find direct ligands for brain TLR4 in heart failure. Further studies are needed to clarify these important questions.ConclusionThe present study suggests that brain TLR4-mediated inflammatory cascade, probably not in plasma and heart, might in part exacerbate LV remodeling with sympathoexcitation in MIinduced heart failure. Although the prevention of LV remodeling and/or sympathoinhibition are necessary in the treatments for MIinduced heart failure and previous many studies have already revealed the pharmacological benefits of several agents, it is also true that we could not prevent MI-induced heart failure via LV remodeling sufficiently. The role of TLR4 in maladaptive MIinduced LV remodeling has been considered to be via inflammatory cytokine production and matrix degradation in heart [31]. Whereas now we have no available methods to inhibit or silencing brain TLR4, the present study provides the important clinical perspectives that brain TLR4 might have a potential to be a new and novel target of the treatments for MI-induced heart failure via prevention for LV remodeling additional to the usual treatments.Methods AnimalThe study was reviewed and approved by the Committee on Ethics of Animal Experiments, Kyushu University Graduate School of Medical Sciences, and conducted according to the Guidelines for Animal Experiments of Kyushu University. Male Sprague-Dawley (SD) rats (250?00 g; SLC, Fukuoka, Japan) were purchased from SLC Japan (Hamamatsu, Japan).Cell CultureRat cell-lines were K162 web cultured under conventional conditions. C6 cells (RIKEN bioresource, Japan) were cultured at 37uC and 5 CO2, in 10 Dulbecco’s Modified Eagle Medium (DMEM) with 10 fetal bovine serum.And TLR4 in vivo and vitro study. In the aspects of cardiac echocardiography, there are discrepancies between the parameters of LV function in the present study. We consider that the discrepancies would be made 1317923 because of the methodological limitations of echocardiography in rats. ICV injection of TLR4-SiRNA improves LV dP/dt and LVEDP, not infarct size and LV fractional shortening. We consider that infarct size and LV fractional shortening are varied data, and the benefits on LV dP/dt and LVEDP are meaningful to a greater extent than infarct size and LV fractional shortening. Moreover, we demonstrated that ICV injection of TLR4-SiRNA improves LVEF and cardiac output. Taking all, we consider that ICV injection of TLR4-SiRNA could improve LV performance in MI-induced heart failure. There are several limitations in the present study. First and the most important limitation is that we could not do the really “silencing” of TLR4 in brainstem by ICV injection of TLR4SiRNA in the present study. Although we tried to do the silencing of TLR4 by TLR4-SiRNA in higher doses, the expression of TLR4 in brainstem could not really silenced (data not shown). Because the aim of the present study was to decrease TLR4 in brainstem, we accepted ICV injection of TLR4-SiRNA. However, it is not really “silencing”. Second, we did not identify the area in the brain where the activation of TLR4 is occurred, and we also did not do the cite-specific silencing TLR4 for a longer period,especially at 1315463 the nucleus involved in the cardiovascular regulation. Because of these limitations, we could not determine the benefits of silencing brain TLR4 on the survival. To clarify these issues, we should do really silencing brain TLR4 for several months by other methods in a future. Finally, we still did not find direct ligands for brain TLR4 in heart failure. Further studies are needed to clarify these important questions.ConclusionThe present study suggests that brain TLR4-mediated inflammatory cascade, probably not in plasma and heart, might in part exacerbate LV remodeling with sympathoexcitation in MIinduced heart failure. Although the prevention of LV remodeling and/or sympathoinhibition are necessary in the treatments for MIinduced heart failure and previous many studies have already revealed the pharmacological benefits of several agents, it is also true that we could not prevent MI-induced heart failure via LV remodeling sufficiently. The role of TLR4 in maladaptive MIinduced LV remodeling has been considered to be via inflammatory cytokine production and matrix degradation in heart [31]. Whereas now we have no available methods to inhibit or silencing brain TLR4, the present study provides the important clinical perspectives that brain TLR4 might have a potential to be a new and novel target of the treatments for MI-induced heart failure via prevention for LV remodeling additional to the usual treatments.Methods AnimalThe study was reviewed and approved by the Committee on Ethics of Animal Experiments, Kyushu University Graduate School of Medical Sciences, and conducted according to the Guidelines for Animal Experiments of Kyushu University. Male Sprague-Dawley (SD) rats (250?00 g; SLC, Fukuoka, Japan) were purchased from SLC Japan (Hamamatsu, Japan).Cell CultureRat cell-lines were cultured under conventional conditions. C6 cells (RIKEN bioresource, Japan) were cultured at 37uC and 5 CO2, in 10 Dulbecco’s Modified Eagle Medium (DMEM) with 10 fetal bovine serum.
