Objectives To establish a new transgenic mouse model for determining the function and role of human scavenger receptor A (SR-A) in atherosclerosis in vivo. Methods Human scavenger receptor minigene-driven mouse tie-1 promoter was constructed and confirmed by endonuclease digestion and sequence analysis. Transgenic mice were generated via the microinjection method. PCR and Southern blot were used to screen the positive transgenic mice. RT-PCR and immunohistochemical analysis were used to detect the level and location of human SR-A Ⅰ expression in transgenic mice. The activity of human SR-A Ⅰ was determined by morphologic observation of aortic endothelial cells of transgenic mice under transmission electron microscopy. Results The electrophoresis assay showed the expected 4 fragments of 0.9 kb, 1.1 kb, 1.2 kb and 4.2 kb in the Sma Ⅰ digest and 2 fragments of 0.8 kb and 6.7 kb in Bgl Ⅱ digest of plasmids pTie-1/hSR-A. The fragment sequence of tie-1 promoter and human SR-A cDNA in plasmids pTie-1/hSR-A was correct and no ATG before the translation initiation sites of human SR-A was found by sequence analysis. 561 injected and surviving embryos with the purified human SR-A minigene were implanted into the oviducts of 19 ICR pseudopregnant mice. Among the 54 surviving pups from 13 foster mothers, 7 were identified by PCR and Southern blot analysis. The results of RT-PCR and imrnunohistochemical analysis showed human SR-A was specifically expressed on vascular endothelial cells of the aorta and renal artery, as well as hepatic sinusoidal endothelial cells in transgenic mice. Transmmion electron microscope (TEM) of aorta of transgenic mice showed that a large number of vesicles, multivesicle bodies and swollen mitochondria filled the plasma of endothelial cells. Conclusions A transgenic mouse model with overexpression of human SR-A in endothelial cells was successfully established. The transgene was integrated and transmitted into the chromosome of transgenic mice. Tie-1 promoter controlled the transgene to express in endothelial cells in mice. Pinocytic activity of aortic endothelial cells in transgenic mice was higher than that of C57BL/6J mice. Our studies will provide a new transcgenic model for investigation of atherosclerosis and functions of human SR-A.

BACKGROUND: We evaluated multiplex PCR for species identification and toxin typing to improve the sensitivity and turnaround time of toxigenic Clostridium difficile culture (TCDC). METHODS: We performed multiplex PCR using primers targeting the species-specific gene, tpi, and the toxin genes, tcdA and tcdB. From January to March 2008, 528 stool specimens were tested with direct toxin assay (DT) using C. difficile Tox A/B II (Techlab, Blacksburg, USA) and TCDC. For 288 specimens from early study period, toxin production by C. difficile isolates of TCDC was measured by enzyme immunoassay with culture supernatants using VIDAS C. difficile Toxin A&B (CDAB;bioMerieux, Marcy-l'Etoile, France) and multiplex PCR with isolated colonies. For 240 specimens from late period, only multiplex PCR was used to test toxin production by the isolates. RESULTS: During the early period, 29 C. difficile were isolated and their toxin-positive rates were 65.5% by PCR and 44.8% by CDAB (P<0.05). Among 528 stool specimens, the results of DT+/TCDC+, DT+/ TCDC-, and DT-/TCDC+ were 32 (6.1%), 33 (6.3%), and 10 (1.9%), respectively, when tested with PCR. 13.3% of total 75 positive specimens was detected only by TCDC. Of the 42 toxigenic C. difficile isolates, all were positive for tpi, 30 (71.4%) were tcdA+/tcdB+, and 12 (28.6%) were tcdA-/tcdB+. CONCLUSION: TCDC using multiplex PCR for species identification and toxin typing is sensitive and rapid to be used as a routine diagnostic test.
Boron Compounds ; Clostridium ; Clostridium difficile ; Diagnostic Tests, Routine ; Immunoenzyme Techniques ; Multiplex Polymerase Chain Reaction ; Polymerase Chain Reaction

[Objective]To investigate the protective effect of Zhuangtongyin on the Middle Cerebral Artery Occlusion(MCAO)model by modulating ferroptosis through the Nrf2-SCL7A11/xCT-Gpx4 pathway and its underlying mechanism.[Methods]C57BL/6J mice were randomly divided into Sham operation group(Sham),model group(MCAO),low-dose Zhuangtongyin group(ZTY-L),high-dose Zhuangtongyin group(ZTY-H),with 5 mice in each group.The MCAO group was modelled by silica gel embolization,the middle cerebral artery of mice was embolized for 1h,then the silica gel was pulled out and reperfusion was performed after 72 h;and the other operations in the Sham group were the same as those in the MCAO group except that the thread plug was not inserted.The neural function of mice was evaluated by Zea-Longa method.TTC staining was used to evaluate the volume of cerebral infarction.The level of brain injury was evaluated by HE staining and Nissl staining.Prussian blue staining and the expression of iron transport-related carrier receptors TfR1 and DMT1 on mRNA level was detected by qPCR to evaluate the iron ion deposition level in mice brain.The expression of lipid peroxidation-related gene ACSL4 on mRNA level was detected by qPCR,and the content of 4-HNE was detected by ELISA kit to evaluate the lipid peroxidation level of mice brain.The expressions of ferroptosis marker PTGS2 mRNA level was detected by qPCR.The expressions of Nrf2,SCL7A11/xCT,Gpx4 in mice brain tissue were detected by Western-blot and immunofluorescence.[Results]Zhuangtongyin improved the nerve function of mice after MCAO(P＜0.05)and the cerebral infarction volume of mice(P＜0.05)and alleviate the pathological injury of cerebral cortex cells after MCAO operation.Zhuangtongyin attenuated the accumulation of trivalent iron ions in the brain tissue of mice following MCAO.Additionally,Zhuangtongyin downregulated the expression of TfR1 and DMT1 mRNA(P＜0.001),a transporter associated with cellular iron ion uptake,in the brains of post-MCAO mice.Furthermore,Zhuangtongyin reduced levels of lipid peroxidation product 4-HNE(P＜0.001)and suppressed ACSL4 mRNA expression in brain tissue post-MCAO(P＜0.001).Besides,Zhuangtongyin downregulated the expression of PTGS2 mRNA(P＜0.001),in the brains of post-MCAO mice.Zhuangtongyin increased the expression of nrf2 into the nucleus(P＜0.001),and increased the expression of xCT and Gpx4 in neurons after MCAO(P＜0.001).[Conclusion]Zhuangtongyin can enhance the nerve function and reduce cerebral infarction volume in MCAO/R mice,alleviate the pathological damage of cerebral cortex cells,and modulate the expression of key signaling molecules in the Nrf2-SCL7A11/xCT-Gpx4 pathway.Therefore,it is suggested that the mechanism by which Zhuangtongyin improves MCAO/R injury in mice may involve regulating ferroptosis through the Nrf2-SCL7A11/xCT-GPX4 pathway.