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.

Ultrasound-guided platelet-rich plasma injection for repair of sciatic nerve crush injury / 中国组织工程研究

BACKGROUND: Platelet-rich plasma (PRP) contains growth factors that affect tendon, ligament, muscle and bone healing. On this basis, researchers gradually realize that such molecules released after PRP activation can regulate the early inflammation of peripheral nerve injury, activate Schwann cells, promote the polarization of macrophages, and actively prevent the hyperplasia of collagen fibers, thus becoming the key drivers of nerve function recovery. OBJECTIVE: To evaluate the value of ultrasound-guided PRP injection in the repair of sciatic nerve crush injury. METHODS: Twenty-eight healthy New Zealand white rabbits (provided by the Beijing Longan Experimental Animal Breeding Center) were randomly divided into normal group, control group, single PRP group and multiple PRPs group. In the normal group, the right sciatic nerve was exposed and then sutured directly. In the control group, a compression injury model of the right sciatic nerve was established. In the single PRP group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling. In the multiple PRPs group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling, and then the PRP injection was performed once at the 3rd and 5th weeks after modeling. Histological and morphological observation of regenerated nerves, wet weight recovery and histological manifestations of the denervated muscle were evaluated at 12 weeks after modeling. The study protocol was approved by the Administrative Committee of Experimental Animals in PLA General Hospital with the approval No. 2015-x10-02. RESULTS AND CONCLUSION: The integral optical density values of NF-200 and S100 staining, myelinated nerve fiber density, myelinated nerve fiber diameter and myelin sheath thickness were significantly increased in the single PRP and multiple PRPs groups compared with the control group (all P < 0.05), and the multiple PRPs group showed better outcomes than the single PRP group (all P < 0.05), but was still inferior to the normal group (all P < 0.05). Compared with the control group, wet weight and cross-sectional area of muscle fibers significantly increased in the single PRP group and multiple PRPs group (P < 0.05), and the multiple RPRs group showed better outcomes than the single PRP group, but was still inferior to the normal group (P < 0.05). To conclude, ultrasound-guided multi-frequency injection of autologous PRP has a good effect on the repair of sciatic nerve crush injury.

Quantitative Evaluation of Sciatic Nerve Crush Injury with Conventional Ultrasound Combined with Shear-wave Elastography in Rabbit Models / 中国医学科学院学报

To explore the value of conventional ultrasound combined with shear-wave elastography in the quantitative evaluation of sciatic nerve crush injury in rabbit models. Forty healthy male New Zealand white rabbits were randomly divided into four groups (=10 in each group):three crush injury (CI) groups (2,4,and 8 weeks after crush) and control group (without injury). The thickness and stiffness of the crushed sciatic nerves and denervated triceps surae muscles were measured at different time points and compared with histopathologic parameters. Inter-reader variability was assessed with intraclass correlation coefficients. Compared with the control group,the inner diameters of the sciatic nerves significantly increased in the 2-week CI group [(1.65±0.34) mm (0.97±0.15) mm,=0.00] but recovered to the nearly normal level in the 8-week CI group [(1.12±0.18) mm (0.97±0.15) mm,=0.06];however,compared with control group [(8.75±1.02)kPa],the elastic modulus of the nerves increased significantly in all the CI groups [2-week:(14.77±2.53) kPa;4-week:(19.12±3.46) kPa;and 8-week:(28.39±5.26) kPa;all =0.00];pathologically,massive hyperplasia of collagen fibers were found in the nerve tissues. The thickness of denervated triceps surae muscle decreased gradually,and the elastic modulus decreased 2 weeks after injury but increased gradually in the following 6 weeks;pathologically,massive hyperplasia of collagen fibers and adipocytes infiltration were visible,along with decreased muscle wet-weight ratio and muscle fiber cross-sectional area. The inter-reader agreements were good. Conventional ultrasound combined with shear-wave elastography is feasible for the quantitative evaluation of the morphological and mechanical properties of crushed nerves and denervated muscles.

Effect of Tai Ji Quan Training on Strength and Function of Lower Limbs in the Aged / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of Tai Ji Quan (TJQ) training on strength and function of lower limbs in the aged.</p><p><b>METHODS</b>Sixty senile subjects were recruited and assigned to the TJQ group and the control group (imparting health knowledge)by random digit table. Patients in the TJQ group received 24-style TJQ training for 18 months (60 min each time, 5 times per week), while those in the control group were imparted with sarcopenia related causes, pathogeneses, prevention and control measures. The maximum isometric strength of bilateral iliopsoas, quadriceps femoris, tibialis anterior muscle, hamstrings; the time for 5 sitting-up tests and Time Up and Go Test (TUGT), one-leg standing time with closed eyes test; and the score of Berg balance scale were compared between the two groups.</p><p><b>RESULTS</b>Compared with before treatment, muscle strength increased in the TJQ group with an average increased capacity (rate) as follows, bilateral iliopsoas 5.5 kg (16.9%), quadriceps femoris 5.5 kg (26.2%), and tibialis anterior muscle 8.5 kg (36.2%) (all P < 0.05). The time for TUGT and 5 sitting-up tests was shortened by 1.3 s (16.7%) and 0.9 s (14.5%) respectively in the TJQ group. The time for one-leg standing time with closed eyes test was increased by 8.4 s (left) and 9.1 s (right) respectively. The score of Berg balance scale increased by 4.3% (P < 0.05). Compared with the control group, bilateral quadriceps femoris and tibialis anterior muscle strength increased significantly (P < 0.01); the time for TUGT and 5 sitting-up tests, the time for one-leg standing time with closed eyes test, scores of Berg balance scale were all improved in the TJQ group after intervention (P < 0.05).</p><p><b>CONCLUSION</b>TJQ training could improve strength of iliopsoas, quadriceps femoris, tibialis anterior muscle in the aged, elevate their balance and locomotor activities, and possibly prevent and treat sarcopenia.</p>