Quercetin Alleviates Lipopolysaccharide-Induced Cardiac Inflammation via Inhibiting Autophagy and Programmed Cell Death

Objective The aim of this study is to explore the potential modulatory role of quercetin against Endotoxin or lipopolysaccharide(LPS)induced septic cardiac dysfunction.Methods Specific pathogen-free chicken embryos(n=120)were allocated untreated control,phosphate buffer solution(PBS)vehicle,PBS with ethanol vehicle,LPS(500 ng/egg),LPS with quercetin treatment(10,20,or 40 nmol/egg,respectively),Quercetin groups(10,20,or 40 nmol/egg).Fifteenday-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity.At embryonic day 19,the hearts of the embryos were collected for histopathological examination,RNA extraction,real-time polymerase chain reaction,immunohistochemical investigations,and Western blotting.Results They demonstrated that the heart presented inflammatory responses after LPS induction.The LPS-induced higher mRNA expressions of inflammation-related factors(TLR4,TNFα,MYD88,NF-κB1,IFNγ,IL-1β,IL-8,IL-6,IL-10,p38,MMP3,and MMP9)were blocked by quercetin with three dosages.Quercetin significantly decreased immunopositivity to TLR4 and MMP9 in the treatment group when compared with the LPS group.Quercetin significantly decreased protein expressions of TLR4,IFNγ,MMP3,and MMP9 when compared with the LPS group.Quercetin treatment prevented LPS-induced increase in the mRNA expression of Claudin 1 and ZO-1,and significantly decreased protein expression of claudin 1 when compared with the LPS group.Quercetin significantly downregulated autophagyrelated gene expressions(PPARα,SGLT1,APOA4,AMPKα1,AMPKα2,ATG5,ATG7,Beclin-1,and LC3B)and programmed cell death(Fas,Bcl-2,CASP1,CASP12,CASP3,and RIPK1)after LPS induction.Quercetin significantly decreased immunopositivity to APOA4,AMPKα2,and LC3-II/LC3-I in the treatment group when compared with the LPS group.Quercetin significantly decreased protein expressions of AMPKα1,LC3-I,and LC3-II.Quercetin significantly decreased the protein expression to CASP1 and CASP3 by immunohistochemical investigation or Western blotting in treatment group when compared with LPS group.Conclusion Quercetin alleviates cardiac inflammation induced by LPS through modulating autophagy,programmed cell death,and myocardiocytes permeability.

Effect of dl-praeruptorin A on desmin and vimentin content in rat ischemia/reperfusion myocardiocytes

Background Intermediate filament （IF） proteins have been thought to play a role in nuclear centration, organelle movement and maintenance of cell shape, dl-praeruptorin A （Pd-la）, a novel Ca^2＋-influx blocker and K^＋-channel opener isolated from Chinese traditional herbal medicine Qian-Hu, has been demonstrated to inhibit expression of apoptosis related proteins and reduce the level of proinflammatory factors in ischemia/reperfusion myocardiocytes. Morphologically, whether Pd-la effects myocardiocyte IFs remains unclear. The purpose of this study was, for the first time, to evaluate the in vivo effects of Pd-la on IF desmin and vimentin content in order to further explore its cardioprotection against ischemia and elucidate its mechanism of action. Methods Rats underwent a 30 minutes coronary occlusion followed by 120 minutes reperfusion. Assessment of desmin and vimentin content of myocardiocytes was performed by immunohistochemistry, Western blot, Hematoxylin-Eosin staining and densitometry. Results Pretreatment with i.v. infusion of Pd-la prior to ischemia significantly increased desmin and vimentin content and alleviated defects caused by the ischemia/reperfusion insult, e.g. with Pd-la at a dose of 0.5 or 1.0 mg/kg, integrated density values of desmin were increased from 61 478 ± 10 074 to 177 408 ±10 395 and 195 784±20 057, and vimentin from 59 189± 19 853 to 164 781± 19 543 and 185 696± 20 957 （P〈0.01, vs placebo）, respectively. The recovery of desmin seemed to be stronger and appeared earlier than that of vimentin. Conclusion Pd-la protectively increased IF desmin and vimentin content in ischemia/reperfusion myocardiocytes, which might be partially responsible for its cardioprotection against ischemia.