Human Platelet-Rich Plasma-Derived Exosomes Promote the Proliferation of Schwann Cells Cultured in Vitro / 中国医学科学院学报

Objective To investigate the effect of human platelet-rich plasma-derived exosomes(PRP-exos)on the proliferation of Schwann cell(SC)cultured in vitro. Methods PRP-exos were extracted by polymerization-precipitation combined with ultracentrifugation.The morphology of PRP-exos was observed by transmission electron microscopy,and the concentration and particle size distribution of PRP-exos were determined by nanoparticle tracking analysis.Western blotting was employed to determine the expression of the marker proteins CD63,CD81,and CD9 on exosome surface and the platelet membrane glycoprotein CD41.The SCs of rats were isolated and cultured,and the expression of the SC marker S100β was detected by immunofluorescence staining.The fluorescently labeled PRP-exos were co-cultured with SCs in vitro for observation of their interaction.EdU assay was employed to detect the effect of PRP-exos on SC proliferation,and CCK-8 assay to detect the effects of PRP-exos at different concentrations(0,10,20,40,80,and 160 μg/ml)on SC proliferation. Results The extracted PRP-exos appeared as uniform saucer-shaped vesicles with the average particle size of(122.8±38.7)nm and the concentration of 3.5×1012 particles/ml.CD63,CD81,CD9,and CD41 were highly expressed on PRP-exos surface(P<0.001,P=0.025,P=0.004,and P=0.032).The isolated SCs expressed S100β,and PRP-exos could be taken up by SCs.PRP-exos of 40,80,and 160 μg/ml promoted the proliferation of SCs,and that of 40 μg/ml showed the best performance(all P<0.01). Conclusions High concentrations of PRP-exos can be extracted from PRP.PRP-exos can be taken up by SCs and promote the proliferation of SCs cultured in vitro.

Research progress on biosynthetic pathway of apo-carotenoids in Crocus sativus / 中草药

The apo-carotenoid compounds represented by crocins are the main medicinal components of Crocus sativus, which have extensive anti-oxidation, anti-inflammatory, anti-atherosclerosis, anticancer, antidepressant, and other pharmacological activities. Biosynthetic pathways of apo-carotenoids in C. sativus include the traditional upstream route of the synthesis of geranylgeranyl pyrophosphate to zeaxanthin starting from mevalonate, and downstream pathway for the specific synthesis of crocetin and crocin by cleavage of zeaxanthin. This article reviews the recent research of key enzymes involved in the metabolism of apo-carotenoids in C. sativus, which facilitates further analysis of downstream pathways for the synthesis of apo-carotenoid derivatives such as crocin, and further provides a theoretical basis for the use of metabolic engineering methods to increase the production of crocins and other pharmacodynamic substances.

Effects of polyethylene oxide at different concentrations on abdominal aortic blood flow and vascular resistance in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of polyethylene oxide (PEO) solution at different concentrations on abdominal aortic blood flow and vascular resistance in rats and evaluate the safety and drag-reducing effect of PEO solution.</p><p><b>METHODS</b>Thirty-two rats were anesthetized and randomly divided into 4 groups. An ultrasonic flow probe was deployed on the abdominal aorta (5 mm above the common iliac artery) to measure the blood flow. The carotid artery pressure, iliac artery pressure, iliac vein pressure, central venous pressure (CVP) and ECG were also monitored. Saline or different concentrations of PEO [(1x10(-6)(low), 1x10(-5)(middle) and 5x10(-5)(high) g/ml)] were injected in the 4 groups of rats through the caudal vein at a constant rate of 5 ml/h for 20 min, and the changes of the vascular resistance was observed. RESULTS After injections of 1x10(-6) and 1x10(-5) g/ml PEO, the abdominal aortic flow increased significantly (P<0.05) while the vascular resistance was reduced (P(low)=0.052, P(middle)<0.001) as compared to those in the saline control group. Following the injection with 5x10(-5) g/ml PEO, the abdominal aortic flow increased to a threshold in the initial 4 min, after which it rapidly decreased to approach the baseline levels despite continuous infusion. Blood pressure remained stable after the injections except for 5x10(-5) g/mlPEO injection, which resulted in a reduction of the blood pressure by about 10 mmHg (P=0.014). The heart rate and CVP both underwent no significant changes following the injections.</p><p><b>CONCLUSION</b>The drag-reducing effect of PEO is closely related to its concentration, and compared with 1x10(-6) g/ml, 1x10(-5) g/ml PEO more effectively increases the blood flow and decreases the resistance. The effectiveness and safety of EPO are attenuated at a concentration higher than 5x10(-5) g/ml.</p>

Ultrasound-mediated microbubble destruction increases capillary permeability in rat skeletal muscles / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of ultrasound mediated microbubble destruction on capillary permeability in rat skeletal muscles.</p><p><b>METHODS</b>Eighteen SD rats were randomized into 3 groups, namely the Evans blue (EB) group, EB+ultrasound (E+U) group and EB+microbubble+ultrasound (U+E+M) group with corresponding treatments, using EB injected into the carotid artery as the indicator for capillary permeability. The microbubbles were injected through the carotid artery with fixed ultrasound parameters. The spillover of EB was estimated under fluorescence microscope according to the visual staining scores. The contents of EB in the skeletal muscles were calculated according to the standard curve and spectrophotometry.</p><p><b>RESULTS</b>EB spillover was observed around the capillaries in E+U+M group, which had a significantly higher visual score than EB group and E+U group (0 and 0-1, respectively, P<0.05). The EB content was 51.57-/+3.89 microg/g in E+U+M group, also significantly higher than those in EB group (28.99-/+4.67 microg/g) and E+U group (30.99-/+4.11 microg/g) (P<0.05).</p><p><b>CONCLUSION</b>Exposure to both ultrasound and microbubble contrast agents results in increased capillary permeability of rat skeletal muscles, which might be an important mechanisms for gene delivery enhancement by ultrasound contrast agents.</p>