Evaluation of hypocrellin A-loaded lipase sensitive polymer micelles for intervening methicillin-resistant Staphylococcus Aureus antibiotic-resistant bacterial infection.

There is an urgent need for new antibacterial strategies to overcome the emergence of antibiotic resistance. Antibacterial photodynamic therapy (APDT) may be an effective method to deliver photosensitizers for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Here, we report that the photosensitizer hypocrellin A (HA) loaded into lipase-sensitive methoxy poly (ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) micelles showed high anti-MRSA activity in vitro and in vivo by PDT. Once the micelles come into contact with bacteria that secrete lipase, the PCL is degraded to release HA. Our results showed that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of mPEG-PCL/HA micelles after light irradiation were 0.69 and 1.38 mg/L (HA concentration), respectively. In the dark, the MIC and MBC of the micelles were 250 and 500 mg/L (HA concentration), respectively. The fluorescent stain results further demonstrated the photodynamic antibacterial activity of mPEG-PCL/HA micelles. The survival rate of mice subjected to experimental acute peritonitis increased to 86% after treated with the micelles. The polymeric micelles showed low hemolytic activity and biocompatibility, simultaneously preventing aggregation in vivo and enhancing the water solubility of HA. Thus, the photosensitizer HA loaded micelles could be used as APDT for infections caused by bacteria without antibiotic resistance.

[Protective effect of curcumin on oleic-induced acute lung injury in rats].

To investigate the effect of curcumine on acute lung injury induced by oleic acid in rat and the possible mechanism of action. The rats were divided into 6 groups randomly: normal group, control group, curcumine groups (5, 10, 20 mg x kg(-1)) and dexamethasone group (1 mg x kg(-1)). During the experiment, acute lung injury was induced by oleic acid in rat. The changes of dynamic lung compliance were recorded by anrise 2005 pulmonary function test apparatus, light microscope was used to examine histological changes and lung index as well as wet to dry weight ratio was calculated by weighting method. Lung vascular permeability and protein level in BALF were detected by ultraviolet spectrophotometry, and the concentrations of TNF-alpha, IL-6 and IL-10 in BALF were measured by enzyme linked immunosorbent assay (ELISA). The result showed that the changes of pulmonary compliance were inhibited and pulmonary function was improved by curcumine. The OA-induced elevation of lung index was restrained, as well as wet to dry weight ratio, lung vascular permeability, protein level, TNF-alpha (250.4 +/- 21.6 vs. 172.53 +/- 14.88, 122.2 +/- 10.98, 108.69 +/- 3.39) ng x L(-1), IL-6 (763.6 +/- 88.33 vs. 207.41 +/- 15.55, 172.13 +/- 21.91, 142.92 +/- 4.32) ng x L(-1) in BALF in curcumine groups, IL-10 (98.90 +/- 2.99 vs. 208.44 +/- 16.30, 218.43 +/- 6.23, 252.70 +/- 20.58) ng x L(-1) in BALF was increased, respectively significantly. Light microscope findings shown that the impairment in curcumine groups was far less severe than that in model groups. Pretreatment of curcumine showed beneficial effect on acute lung injury induced by oleic acid in rats. The mediation of both proinflammatory factor and anti-inflammatory factor by curcumine may be involved in mechanism of action of curcumine effects.

[Study of the effect of crocin on rat experimental hyperlipemia and the underlying mechanisms].

OBJECTIVE: To study the effect of crocin on rat experimental hyperlipemia and its mechanisms. METHOD: Hyperlipemia model was established by feeding heavy cholesterol for 2 months and the effect of crocin on blood lipid in experimental hyperlipemia rats was observed. Aortic smooth muscle cells were cultured in different culture media and proliferation was measured by MTT assay. Western blotting was used to detect the effect of crocin on phosphorylation of p38 MAPK. RESULT: Crocin not only decreased greatly the content of cholesterol, triglyceride and density lipoprotein in blood, but also increased the content of high density lipoprotein. In addition, the proliferation of smooth muscle cells and the activation of p38MAPK were inhibited by Crocin. CONCLUSION: Crocin prevents atherosclerosis in hyperlipemia, which may be mediated by the inhibition of both proliferation of smooth muscle cells and activation of p38MAPK.