Protective effect of apigenin on ischemia/reperfusion injury of the isolated rat heart.

Apigenin (Api), a mainly bioactive component of Apium graveolens L. var. dulce DC. (a traditional Chinese medicinal herb), possesses a wide range of biological activities, including antioxidant effects. It also has been shown to associate with lower prevalence of cardiovascular diseases, but its mechanisms of action remain unclear. The aim of the present study is to investigate the role of Api in isolated rat heart model of ischemia/reperfusion (I/R). Langendorff-perfused isolated rat hearts were used in our study. Api was added to the perfusate before ischemia and during reperfusion in the isolated pulsed rat heart exposed to 30-min ischemia followed by 50-min reperfusion. The treatment with Api conferred a cardioprotective effect, and the treated hearts demonstrated an improved ischemic cardiac functional recovery, a decreased myocardial infarct size, a reduced activities of creatine kinase isoenzyme and lactate dehydrogenase in the coronary flow, a reduced number of apoptotic cardiomyocytes, a reduced activity of caspase-3, up-regulation of the anti-apoptotic protein Bcl-2 and down-regulation of the pro-apoptotic protein Bax. In addition, Api inhibited the phosphorylation of p38 MAPKS during I/R. In conclusion, these observations provide preliminary evidence that Api can protect cardiomyocytes from I-/R-induced injury, at least partially, through the inhibition of p38 MAPKS signaling pathway.

Nitric oxide and ATP-sensitive potassium channels mediate lipopolysaccharide-induced depression of central respiratory-like activity in brain slices.

Infection may result in early abnormalities in respiratory movement, and the mechanism may involve central and peripheral factors. Peripheral mechanisms include lung injury and alterations in electrolytes and body temperature, but the central mechanisms remain unclear. In the present study, brainstem slices harvested from rats were stimulated with lipopolysaccharide at different doses. Central respiratory activities as demonstrated by electrophysiological activity of the hypoglossal rootlets were examined and the mechanisms were investigated by inhibiting nitric oxide synthase and ATP-sensitive potassium channels. As a result, 0.5 µg/ml lipopolysaccharide mainly caused inhibitory responses in both the frequency and the output intensity, while 5 µg/ml lipopolysaccharide caused an early frequency increase followed by delayed decreases in both the frequency and the output intensity. At both concentrations the inhibitory responses were fully reversed by inhibition of nitric oxide synthase with Nω-nitro-L-arginine methyl ester hydrochloride (20 µM), and by inhibition of ATP- sensitive potassium channels with glybenclamide (100 µM). These results show that direct lipopolysaccharide challenge altered central respiratory activity in dose- and time- related manners. Nitric oxide synthase and ATP-sensitive potassium channels may be involved in the respiratory changes.

Association between inflammatory genetic polymorphism and acute lung injury after cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Recently, single nucleotide polymorphisms were proposed as potentially new predictors for perioperative risks, such as myocardial infarction and organ dysfunction. The objectives of this study were to investigate whether IL-6 -572C/G, IL-10 -1082A/G, and TNF-alpha -308G/A were associated with acute lung injury after cardiac surgery with cardiopulmonary bypass. MATERIAL/METHODS: One hundred patients with acute lung injury at 24 hours after cardiac surgery with cardiopulmonary bypass and 112 patients without acute lung injury as controls were included. Genotyping assay was performed with real-time fluorescence-based allele-specific PCR. Serum levels of IL-6, IL-10, and TNF-alpha were also determined by ELISA. Associations between these polymorphisms and acute lung injury, as well as serum cytokine levels, were analyzed. All patients were genotyped for IL-6 -572C/G, IL-10 -1082A/G, and TNF-alpha -308G/A. Circulating level of these cytokines were also determined. RESULTS: Acute lung injury after cardiac surgery with cardiopulmonary bypass was associated with IL-6 -572C/G polymorphism, but not IL-10 -1082A/G or TNF-alpha -308G/A. This functional polymorphism was further confirmed by multivariate analyses. The ratio of circulating concentrations of IL-10/IL-6 was associated with IL-6 genotypes and incidence of acute lung injury as well. CONCLUSIONS: The IL-6 -572 polymorphism was associated with acute lung injury after cardiac surgery with cardiopulmonary bypass. Proinflammatory and anti-inflammatory imbalance might be the clinical significance of IL-6 polymorphism (ClinicalTrials.gov number, NCT00826072).