[Feasibility of echocardiography-guided repeated intraventricular blood sampling in mice].

Objective: To investigate the feasibility of echocardiography-guided closed-chest repeated intraventricular blood sampling in mice, and to clarify the maximum blood volume that can be collected by this method, and whether the method can be used for long-term repeated blood collection in mice. Methods: Twenty-four male C57BL/6J mice (10-14 weeks old) were divided into the terminal experiment group (n=4, for investigating the maximum blood amount that could be sampled at one time), the repeated 0.5 ml blood collection group (n=10, sampling 0.5 ml whole blood each time, once every two days for consecutive 4 weeks), and the repeated 0.75 ml blood collection group (n=10, sampling 0.75 ml whole blood each time, once every two days for consecutive 4 weeks). High-frequency echocardiography was used to display the largest section of the left ventricle, guiding the insulin syringe needle through the thorax into the left ventricle for blood collection. In the repeated 0.5 ml blood collection group, echocardiography was used to detect the cardiac structure and function before blood collection, three minutes after blood collection, and one week after the last (the 14th) blood collection. Results: We successfully performed echocardiography-guided closed-chest intraventricular blood sampling, with an average operating time (88±19)s per mouse, and a maximum blood volume (1.43±0.11)ml per mouse. In the repeated 0.5 ml blood collection group, heart rate, left ventricular ejection fraction, left ventricular fractional shortening, left ventricular end-diastolic dimension and left ventricular posterior wall end-diastolic thickness remained uncganged before the first blood collection and after 4 weeks of repeated blood collection (all P>0.05). No death in the repeated 0.5 ml blood collection group. However, in the 0.75 ml blood collection group, two mice died before the end point. Conclusions: The echocardiography-guided closed-chest intraventricular blood sampling is a safe, minimally invasive, convenient and efficient method, and can be used repeatedly for long-term blood collection in mice.

Development of a rinsing separation method for exosome isolation and comparison to conventional methods.

OBJECTIVE: Exosomes contain valuable biomarkers for many diseases. Tragically, standardized isolation methods and subsequent characterization criteria for exosomes remain limited. Therefore, we developed a new exosome isolation method, termed rinsing separation, and compared its advantages and weaknesses relative to the existing ultracentrifugation and ExoQuick precipitation methods. MATERIALS AND METHODS: Rinsing separation utilizes heparin and glutaraldehyde as a fixative to isolate exosomes, and was developed using the culture supernatant from mesenchymal stem cells (MSCs). The isolated exosomes were characterized and compared by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western blot. RESULTS: Consistent with known exosome parameters, exosomes isolated using each method ranged in size from 30 to 150 nm and demonstrated the characteristic cup-shaped morphology. Moreover, the exosome markers CD63 and TSG101 were observed in the lysate of all exosome samples that were isolated using each method. Several advantages and drawbacks were noted for each exosome isolation method. Most notably, ultracentrifugation resulted in fewer, but highly pure, exosomes, and samples generated using the ExoQuick precipitation method contained the most contaminating debris. Samples obtained using pour rinsing separation method represented an amalgam of these two fractions, but were isolated in significantly less time. CONCLUSIONS: In this study, we propose rinsing separation as a new method of isolating exosomes. This method is convenient, and the resulting exosomes are highly pure. Moreover, rinsing separation offers time- and cost-efficiency advantages, making it a promising approach for exosome isolation for clinical applications.

Effect of odanacatib on root resorption and alveolar bone metabolism during orthodontic tooth movement.

The aim of this study was to investigate the effect of local administration of odanacatib (ODN) on orthodontic root resorption and the status of alveolar bone metabolism in rat molars. All specimens were scanned using microcomputed tomography and then the raw images were reconstructed. The total volume of the root resorption craters of the 60 g-NS (normal saline) group was higher than in the 60 g-ODN group and the control group. In the 60 g-NS group, the bone volume fraction values of alveolar bone were significantly decreased compared with the other 2 groups. There were no significant differences in the bone volume fraction values of the tibiae among the 3 groups. The results of tartrate-resistant acid phosphatase-positive (TRAP+) numbers showed that there was no difference between the 60 g-NS group and the 60 g-ODN group. The expression of cathepsin K was decreased significantly in the 60 g-ODN group. These results indicate that ODN reduces orthodontics-induced external root resorption and increases alveolar bone metabolism. This may be because ODN inhibits the activity of odontoclasts, but maintains the quantity of odontoclasts and enhances bone formation. ODN promotes local alveolar bone metabolism, but does not affect systemic bone metabolism.

The therapeutic effect of rosuvastatin on cardiac remodelling from hypertrophy to fibrosis during the end-stage hypertension in rats.

End-stage hypertensive heart disease is an increasing cause of cardiac mortality. Therefore, the current study focused on the cardiac remodelling from hypertrophy to fibrosis in old-aged spontaneously hypertensive rats (SHRs), and explored the therapeutic effects of Rosuvastatin and its possible mechanism(s) of action. Spontaneously hypertensive rats at age 52 weeks were randomly divided into three groups, the first two to receive Rosuvastatin at a dose of 20 mg/kg/day and 40 mg/kg/day, respectively, and the third to receive placebo, which was to be compared with Wistar-Kyoto as controls. After 2-month treatment, SBP, heart to body weight ratio (HW/BW%) and echocardiographic features were evaluated, followed by haematoxylin and eosin and Masson trichrome staining in conjunction with qPCR of foetal gene expressions. Transferase-mediated dUTP nick-end labelling assay and immunofluorescent labelling for active caspase-3 were used to detect the apoptotic cardiomyocytes. Signaling pathways involved were examined by using western blot. Old-aged SHR developed end-stage hypertensive heart disease characterized by significant enhancement of HW/BW%, LVAWd and LVPWd, and decreased LVEF and LVFS, accompanied by cardiomyocytes enlargement and fibrosis along with activation of foetal gene programme. Cardiac apoptosis increased significantly during the transition process. Rosuvastatin reduced hypertrophy significantly via AT(1) Receptor-PKCß2/α-ERK-c-fos pathway; protected myocardium against apoptosis via Akt-FOXO1, Bcl-2 family and survivin pathways and consequently suppressed the caspase-3 activity. The present study revealed that old-aged SHRs developed cardiac remodelling from hypertrophy to fibrosis via cardiac apoptosis during the end stage of hypertensive heart disease. These pathological changes might be the consequence of activation of AT(1) Receptor-PKCß2/α-ERK-c-fos and AKT-FOXO1/Bcl-2/survivin/Caspase3 signaling. Rosuvastatin effectively attenuated the structural changes by reversing the signaling transductions involved.