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Objective:To prepare liquid-gas phase modified nanoparticles (TMZ/PFP/PLGA NPs) of perfluoropentane (PFP) and temozolomide (TMZ) encapsulated by polylactic-glycolic acid copolymer (PLGA), combined with low intensity focused ultrasound (LIFU) irradiation, and to investigate its ultrasound imaging ability and intervention effect on human glioma cells in vitro.Methods:TMZ/PFP/PLGA NPs were prepared by compound emulsion method. The basic physical and chemical properties and drug loading ability of TMZ/PFP/PLGA NPs were detected. CCK-8 assay was used to detect the cytotoxicity of nanoparticles in vitro and the effect of synergistic intervention with LIFU on the survival rate of glioma cells. The expression levels of apoptosis related proteins Bcl-2, Bax and caspase-3 were detected by Western blot.Results:Under transmission electron microscope, TMZ/PFP/PLGA NPs showed a circular core-shell structure with regular morphology, particle size was (137.9±63.31)nm, encapsulation efficiency of TMZ was (83.01±5.57)%, drug loading was (3.19±0.22)%. The survival rate of U251 cells was still above 70% after 24 hours of co-incubation with nanoparticles. Under the synergistic effect of LIFU irradiation, the apoptosis of U251 cells was accelerated and the survival rate of U251 cells was significantly decreased. The results of Western blot showed that the synergic intervention could significantly down-regulate the expression of apoptosis related protein Bcl-2, and significantly up-regulate the expression of Bax protein and caspase-3 protein (all P<0.05). Conclusions:TMZ/PFP/PLGA NPs have good basic physical and chemical properties. TMZ/PFP/PLGA NPs have low cytotoxicity in vitro while efficiently loading chemotherapeutic drug timozolomide. Synergistic intervention under LIFU irradiation can significantly accelerate the apoptosis of U251 glioma cells, which has a good application prospect.
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Objective:To study the efficacy of low-intensity focused ultrasound (LIFU) on neuropathic pain (NP) in mice, and its effect on the activation of astrocytes and the expression of pro-inflammatory cytokines were discussed.Methods:Thirty-six male C57BL/6J mice were randomly divided into three groups: sham operation (Sham) group and chroinc constriction injury (CCI) model group and treatment (CCI+ LIFU) group, 12 mice in each group.NP model was established by CCI on the sciatic nerve. The group of CCI+ LIFU received LIFU treatment for the anterior cingulate cortex (ACC) on the 7th day after surgery, the mechanical withdrawal threshold (MWT) on the affected side of mice was measured at preoperation 3, 6, 12, 18, 24, and 27 days after operation, respectively, H&E staining was used to observe pathological morphological changes in the ACC region, the expression levels of ACC region AQP4 and GFAP protein were detected by Western Blot and immunofluorescence, and the expression levels of ACC region pro-inflammatory cytokines IL-1β and TNF-α were detected by enzyme-linked immunosorption assay.Results:Compared with Sham group, MWT in the CCI group decreased from the 3rd day until the 27th day after surgery( P<0.05); Compared with the CCI group, the MWT in the CCI+ LIFU group increased on the 24th day after surgery, and was significantly higher than that of the CCI group on the 24th and 27th day after surgery ( P<0.05); LIFU stimulation did not produce significant pathological changes in the ACC region; Western Blot and immunofluorescence showed that AQP4 and GFAP protein expression in the ACC region were upregulated ( P<0.05) after peripheral nerve injury, while AQP4 and GFAP protein expression was downregulated after LIFU treatment ( P<0.05); Enzyme-linked immunosorbents showed that the expression of pro-inflammatory cytokines IL-1β and TNF-α in the region of ACC was upregulated ( P<0.05) after peripheral nerve injury, while the expression of IL-1β and TNF-α was downregulated after LIFU treatment ( P<0.05). Conclusions:LIFU can effectively relieve mechanical pain sensitivity symptoms in mice induced by CCI, possibly by inhibiting activation of astrocytes and neuro-inflammatory responses.
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Objective To prepare a novel ultrasound contrast agent , targeted phase-shift lipid nanoparticles mediated by tumor homing and penetrating peptide tLyP-1 ,and to evaluate its characteristics . Methods The nanoparticles were prepared by filming-rehydration and acoustic-vibration methods .The morphology ,distribution ,particle size and zeta potential were detected . After heating and irradiating of low intensity focused ultrasound ( LIFU) ,the phase-shift characteristic and the enhancement effect in vitro were observed . The tumor homing and cell-penetrating properties of the nanoparticles were examined by confocal laser scanning microscopy and flow cytometry . The cytotoxicity of the nanoparticles was evaluated by CCK 8 assay . Results The size and distribution of nanoparticles were uniformed . The size and zeta potential of nanoparticles were ( 399 .50 ± 29 .98) nm and ( 3 .28 ± 1 .72) mV ,respectively . When the nanoparticles were heated to a temperature of 45 ℃ or after irradiated by LIFU ,nanoparticles generated phase-shift and enhanced ultrasound imaging in vitro ( P 0 .05 ) . Conclusions A novel ultrasound contrast agent , targeted phase-shift lipid nanoparticles mediated by tumor homing and penetrating peptide tLyP-1 ,is prepared successfully . It can target to MDA-MB-231 cell and penetrate into the cell in vitro ,and enhance ultrasound imaging in vitro after LIFU irradiation ,which expected to become a novel tumor targeted ultrasound contrast agent and achieve ultrasound molecular imaging at the level of tumor cell .