Abstract: Objective To evaluate the protective effect of quercetin against lipopolysaccharide (LPS)-induced cardiac injury in
mice. Methods C57BL/6J mice were randomized into 4 groups to receive intraperitoneal injection of saline (negative control) or
LPS (20 mg/kg), or fed with quercetin (100 mg/kg for 7 days) with or without subsequent LPS injection (quercetin+LPS group
and quercetin control group, respectively). Six hour after LPS injection, the mice were tested for cardiac function with an
echocardiograph, and the protein expressions of Bax, Bcl-2, iNOS, and eNOS in the myocardium were evaluated with Western
blotting; serum NO concentration was also measured. The survival of the mice within 5 days after LPS injection was recorded
to draw the survival curve. Results Quercetin pretreatment significantly improved the cardiac function of LPS-challenged
mice (P<0.05), and attenuated LPS-induced increment in myocardial iNOS expression and decrement in eNOS level. LPS
significantly increased the myocardial Bax expression and slightly decreased Bcl-2 expression; quercetin pretreatment
decreased Bax expression to the control level and significantly lowered Bax/Bcl-2 ratio as compared with the LPS group. Serum
NO level was significantly increased by nearly 2.5 folds in LPS-challenged mice, but was markedly decreased with quercetin
pretreatment (P<0.05). The 5-day survival rate of LPS-treated mice was 10% , which was increased to 45% in quercetinpretreated
mice (P<0.05). Conclusion Quercetin can alleviate LPS-induced cardiac dysfunctions in mice to increase their
survival rate following LPS challenge.