Objective: To investigate the influence of intermittent cold stress on collagen content of atherosclerotic plaque in experimental ApoE-/-mice.
Methods: A total of 20 male ApoE-/-mice at 8 weeks of age were divided into 2 groups:Experimental group, the mice had intermittent cold exposure at (4 ± 1)°C from 8am to 12noon and Control group, the mice were living at (24 ± 2) °C. All animals were treated for 12 weeks, n=10 in each group. The collagen content of atherosclerotic plaque at the aortic root in ApoE-/-mice was observed by Masson staining, the protein expressions of aortic MMP-2, MMP-9 and TIMP-1 were examined by Western blot analysis.
Results: Compared with Control group, the Experimental group presented the lower collagen content of atherosclerotic plaque at the aortic root, higher protein expressions of MMP-2, MMP-9 and lower protein expression of TIMI 1.
Conclusion: Intermittent cold stress may disturb the balance of MMP/TIMP and decrease collagen content of atherosclerotic plaque to form vulnerable plaque in experimental ApoE-/-mice which may cause acute coronary syndrome.

Objective To establish an animal model of calpastatin ( CAST) transgenic mice by inserting the full hu-man CAST into the genome of C57BL/6J mice.Methods Recombinant transgenic vector pRP .EX3d-EF1A-CAST-IRES-eGFP was constructed by Gateway technology .It was injected into the fertilized eggs from C 57BL/6J mice.The injected eggs were transplanted into the oviduct of pseudopregnant mice .Tail DNA PCR screening was performed to identify the positive founder mice.The expressions of CAST mRNA and protein in tissues of the transgenic mice were detected by RT -PCR and Western blotting.Results Ninty eggs were transplanted into the oviducts of 3 recipients.The transplantation success rate was 100%.23 viable offsprings were born from the recipients .Tail DNA PCR screening showed that two of the offsprings were positive transgenic mice .The positive rate of transgenic mice was 9%.RT-PCR assay revealed that CAST mRNA ex-pressions were present in the heart , liver, kidney, lung, spleen, brain and skeletal muscle of the transgenic mice .Addition-ally, the CAST protein expression was significantly increased in the transgenic mice .Conclusion CAST transgenic mice have been successfully established and provide a good animal model support for further studies on the CAST function .