Intermittent Cold Stress Reducing the Collagen Content of Atherosclerotic Plaque in Experimental ApoE-/-Mice / 中国循环杂志

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.

Establishment and identification of calpastatin transgenic mouse models / 中国实验动物学报

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 .

Effect of Peroxisome Proliferator-activated Receptor δ Activation on the Expression of Tenascin-C in Infarcted Myocardium / 中国医科大学学报

Objective The purpose of the present study was to investigate the effect of peroxisome proliferator-activated receptors δ（PPAR δ）activation with dietary GW610742X on the expression of tenascin-C in the infarcted and remodeling myocardium.Methods Sixty male Wistar rats were divided into four groups,including control group,sham group,myocardial infarction（MI） group,and MI＋GW610742X（GW）group.The left coronary artery was ligated to establish the MI model.PPAR δ activator GW610742X（100mg/kg/d）was administrated into the rats of GW group.At 3 months after procedure,the expression and distribution of tenascin-C in left ventricular free wall from each group were examined by Western blotting and immunofluorescence,respectively.Results After 3 months following procedure,there were obvious necrosis and fibrosis in left ventricular free wall from MI group.The expression of tenascin-C in MI and GW group was significantly higher than those in control and sham group（P 〈 0.01）.Moreover,tenascin-C expression in GW group was remarkably decreased compared to MI group（P 〈 0.05）.Additionally,tenascin-C expression in sham group was similar to that in control group（P 〉 0.05）.Conclusion The tenascin-C is upregulated in infarcted myocardium during the remodeling process,which can be significantly attenuated by PPAR δ activation.

Capsaicin Inhibits Angiotensin Ⅱ Induced Vasoconstriction in Mice / 中华高血压杂志

Objective To study the long-term effect of administration(6 months) with transient receptor potential vanilloid 1(TRPV1) agonist capsaicin on contractile reactivity of thoracic aorta in C57BL/6J mice.Methods Tow-month-old male C57BL/6J mice were received normal diet group(n=12) or capsaicin group(normal diet plus capsaicin,n=12).Tail-cuff systolic blood pressure(SBP) was examined at the baseline and at the end of the intervention.After 6-month treatment period,carotid artery blood pressure and heart rate were determined by catheterization,and the aortic contractile response was examined using isometric myograph(Danish Myotech Technology,Denmark).Plasma levels of renin,angiotensin Ⅱ(Ang Ⅱ) and aldosterone were determined.Vascular smooth muscle cells(VSMC) were obtained from thoracic aorta of mice and cultured.Angiotensin Ⅱ type 1 receptor(AT1R) protein expression was detected by western blot.Calcium imaging was detected in cultured VSMC using the fluorescent dye technique.Results Systolic blood pressure,invasive carotid artery blood pressure and heart rate have no difference between two groups.No differences was found in PE-induced contraction response in thoracic aorta;while Ang Ⅱ induced contractility of aortic ring was lower in mice with capsaicin than control group [capsaicin:(37.5?1.6)% vs(59.8?1.4)%,P

Biomechanical test and histological observation of human plantaris tendon / 第三军医大学学报

Objective To provide the biomechanical basis of plantaris tendon for clinical autotransplantation. Methods Fifteen plantaris tendons from 8 fresh adult cadavers were cut into 56 segments with about 6 cm lengths in each. The segments were divided into 3 groups: upper,middle,and lower segments. Fifty segments were taken for the tensile test,while the other six segments were loaded under 30 MPa,40 MPa,and 50 MPa respectively. The histologic structure of the tendons was observed under the microscope after presumptive load. Results The average limit load,tensile strength and elastic modulus of the plantaris tendon were (83.19?42.52) N,(60.32?21.80) MPa,and (714.83?285.44) MPa respectively. The tensile strength of the lower segments was significant higher than the upper and middle segments. Conclusion The biomechanical property of the plantaris tendon is accommodative for autografting.