Objective To investitate the efficacy of cannabinoid-2 receptor (CB2R) activation in preventing liver ischemia-reperfusion (I/R) injury in mice.Methods Forty-eight male C57BL/6J mice,weighing 20-30 g,were divided into 4 groups (n =12 each):sham operation group (group S),group I/R,CB2R agonist JWH133 group (group J),and CB2R agonist JWH133 + CB2R antagonist SR144528 group (group JS).Liver I/ R was produced by blocking the hepatic artery and portal vein for 30 min followed by 45 min of reperfusion in anesthetized mice.At 60 min before ischemia,JWH133 20 mg/kg was injected intraperitoneally in group J,and JWH133 20 mg/kg and SR144528 30 mg/kg were injected intraperitoneally in group JS.The liver was removed at 45 min of reperfusion for determination of tumor necrosis factor-α (TNF-α),macrophage inflammatory protein-1α (MIP-1α) and MIP-2 contents (using ELISA),and expression of TNF-α,MIP-1α,MIP-2 and intercellular adhesion molecule-1 (ICAM-1) mRNA (by RT-PCR) in the liver tissues and for microscopic examination of the pathological changes.Results Compared with group S,the contents of TNF-α,MIP-1α and MIP-2 were significantly increased,and the expression of TNF-α,MIP-1α,MIP-2 and ICAM-1 mRNA was up-regulated in J and JS groups.Compared with group I/R,the contents of TNF-α,MIP-1α and MIP-2 were significantly decreased,and the expression of TNF-α,MIP-1α,MIP-2 and ICAM-1 mRNA was down-regulated in J group,and no significant change was found in the parameters mentioned above in JS group.Compared with group J,the contents ofTNF-α,MIP-1α and MIP-2 were significantly increased,and the expression of TNF-α,MIP-1α,MIP-2 and ICAM-1 mRNA was up-regulated in JS group.The pathological changes of liver tissues were significantly attenuated in group J as compared with I/R and JS groups.Conclusion CB2R activation is effective in preventing liver I/R injury in mice and the mechanism is related to inhibitioni of inflammatory responses in liver tissues.

Carnosine (beta-Ala-L-His) has high antioxidant activity, and it is widely used in biology, chemical engineering, medicine and other fields. Its analogue syntheised in non-aqueous solvent and catalyzed by enzymes is high-effective but low-price, so it has great prospect. Here, we synthesized a carnosine analogue imidazole 4(5)-alanylamide-5(4)-carboxylic acid with imidazole-4,5-dicarboxylic acid and L-Alanine as substrates, alpha-chymotrypsin as catalyst in tetrahydrofuran (THF) solvent. Based on the orthogonal experiments, the optimized synthetic conditions are 4,5-dicarboxylic acid: L-alanine = 1:3 (m/m), alpha-chymotrypsin: substrates (4,5-dicarboxyl acid and L-alanine) = 1:200 (m/m), pH 8 phosphate buffer:THF = 1.6:10 (V/V), reaction temperature 35 degrees C, time 1.5 h. We separated the product with silica gel G60 thin-layer chromatography (TLC), and a new spot appeared at Rf (ratio to front) = 0.81; then the new spot was purified and characterized with UV spectra, high performance liquid chromatogram (HPLC) and 13C NMR (13C nuclear magnetic resonance). The UV spectra shows a new absorption peak at 310 nm, and the peak in 253 nm is largely strengthened; HPLC reserve times are all 4.5 min at 253 nm, 310 nm, 330 nm; 13C NMR shows 8 carbons. Combing with the catalytic mechanism of alpha-chymotrypsin, structure of the analogue is confirmed, i.e., imidazole 4(5)-alanylamide-5(4)-carboxylic acid.
Carnosine ; analogs & derivatives ; biosynthesis ; chemistry ; Catalysis ; Chromatography, High Pressure Liquid ; Chymotrypsin ; metabolism ; Furans ; chemistry ; Solvents

Fluoroquinolones are widely used in clinical practice, but their clinical application in juvenile patients has been controversial.The purpose of this study was to investigate the pharmacokinetic characteristics, indications and adverse reactions of Ciprofloxacin and Levofloxacin in minors.It is shown that the two drugs are effective for infectious diseases and no serious or persistent joint or skeletal muscle injury occurs in minors using the drugs.Hence, in the absence of alternatives, the benefits of Ciprofloxacin or Levofloxacin treatment for minors may outweigh the risks.