Objective To establish and identify transgenic mice model that specifically express delta drosophila homolog-like 1 (DLK1) in liver for the functional study of DLK1 on liver differentiation,hepatopathy,and hepatocellular carcinoma.Methods The coding sequence of DLK1 cDNA was inserted downstream of mouse albumin gene enhancer/promoter to construct a liver-specific DLK1 expression recombinant vector.The DNA fragment of transgene digested from the recombinant vector by Pine I was transfected to Hepl-6 cells to verify the expression of DLK1 in vitro.Then the transgene fragment was microinjeeted into fertilized eggs of C57×CBA F1 mice and 20 transgenic founder mice were generated.The F1 mice of DLK1 transgenie founder mice were used to identify the expression of the transgene in liver and other tissues.Results RT-PCR and cellular immunofluorescence showed DLK1 expression when the transgene fragment was transfeeted into Hep1-6.For transgenic mice,RT-PCR and immunohistochemistry showed that DLK1 was specifically expressed in adult F1 mice liver.Conclusion Successfully established the liver-specific DLK1 expression transgenic mice model.

OBJECTIVE:To establish a method for determining recombinant human calmodulin B subunit(rhCNB)in rat plas-ma,and study its pharmacokinetics characteristics. METHODS:ELISA double-antibody sandwich method was adopted. 1 μg/ml rhCNB monoclonal antibody mAb was wrapped,added to the to-be-test sample,rhCNB polyclonal antibody pAb(dilution ratio of 1∶5 000)and HRP-labeled conjugate of anti-IgG(dilution ratio of 1∶10 000)were added. Using tetramethylbenzidine for develop-ing,microplate reader was conducted in wavelength of 450 nm to determine the absorbance value(OD value)and plasma concen-tration of 6 rats after 2,15,30,60,120,240,480,720 min of iv 2.5 mg/kg rhCNB,and the pharmacokinetic parameters were calculated by BAPP 3.0 software. RESULTS:The linear range of rhCNB were 0.195-12.5 ng/ml(r2=0.995 0),lower limit of quan-titation was 0.195 ng/ml,accuracy were 97.300%-103.622%(RSD<7.5%,n=6);RSDs of within-batch,inter-batch,freezing and thawing 3 times were no higher than 8.5%(n=6,18,15). rhCNB pharmacokinetics characteristics in rat fitted to two-com-partment model,AUC0-720 min was 173.038 mg·min/L and t1/2 was 94.62 min. CONCLUSIONS:The established method has high specificity and sensitivity,good accuracy and precision,which can be used for rhCNB quantitative detection and pharmacokinetics study in biological samples.