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This study aimed to prepare silk fibroin nanoparticles (SF-NPs) and assess the physicochemical properties and biocompatibility of the formulation. An optimized and simplified solvent displacement method was employed to obtain SF-NPs. Single-factor prescription screening, such as silk fibroin (SF) solution concentration, the ratio of SF solution to organic solvent, ultrasonication power and time, and different types of organic phases, was used to optimize the formulation. The characterization of the optimal formulation included particle size, polydispersity index (PDI), zeta potential, morphology, and stability. The in vitro cell compatibility of the nanoparticles was evaluated using CCK-8 and Calcein-AM/PI cell viability staining. The results showed that when SF concentration was 20 mg·mL-1, volume ratio of aqueous phase to acetone was 1∶6, ultrasonic power was 80 W and ultrasonic time was 3 min, the best SF-NPs was obtained. The nanoparticles prepared in this study exhibit a near-spherical shape, with a uniform size distribution, having an average size of 144.8 nm, a PDI of 0.174, and a zeta potential of -27.35 mV. Results from in vitro cell experiments demonstrate excellent cell compatibility of SF-NPs, showing the ability to promote cell proliferation. The SF-NPs which were successfully prepared in this study exhibit uniform particle size and excellent biocompatibility.
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Aim To study the apoptosis-inducing effect of rosmarinic acid derivative RAD-9 on gastric cancer MGC-803 cells and the underlying mechanisms.Methods MTT assay was taken to detect the survival of gastric cancer MGC-803 cells effected by RAD-9.Cell apoptosis was detected by flow cytometry.The apoptotic morphology of MGC-803 cells was observed by Hoechst 33258 staining.The protein expression levels of Bcl-2,Bax,caspase-3,Akt,p-Akt,p38 MAPK and p-p38 MAPK were measured by Western blot.Results The results of MTT assay showed that RAD-9 inhibited the viability of gastric cancer MGC-803 cells in a time and concentration-dependent manner.Flow cytometry showed that RAD-9 significantly promoted apoptotic cell percentage in gastric cancer MGC-803 cells (P ＜ 0.01).Hoechst 33258 staining showed that the nucleus of MGC-803 cells could be observed with typical apoptotic morphological changes after RAD-9 administration.Compared with the control group,the protein expression levels of Bcl-2,Akt,p-Akt were significantly down-regulated (P ＜ 0.01),while those of Bax,caspase-3,p38 MAPK,p-p38 MAPK were significantly up-regulated (P ＜ 0.01).Conclusion RAD-9 can inhibit the growth and further induce apoptosis in gastric cancer MGC-803 cells,which may involve inhibiting PI3K/Akt and activating p38 MAPK signaling pathway.
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<p><b>OBJECTIVE</b>To investigate the effect of Cedemex on cAMP and cGMP contents in different brain regions in morphine withdrawal rats precipitated by naloxone.</p><p><b>METHOD</b>A physical morphine dependent model of rats was established by subcutaneous injection of morphine in gradually increasing dosage within 7 days. cAMP and cGMP contents of VTA, cortex and hippocampus of the rat brains were determined by radioimmunoassay.</p><p><b>RESULT</b>The morphine withdrawal symptoms of rats were relieved significantly by ig Cedemex. Compared with the controls, cAMP content in the region of VTA, cortex and hippocampus of the morphine dependent rats were significantly higher (P < 0.05), while cGMP contents in those regions were significantly lower (P < 0.05). cAMP contents in the area of VTA, cortex and hippocampus of the morphine dependent rats were significantly reduced, while cGMP contents were significantly increased by ig Cedemex.</p><p><b>CONCLUSION</b>Cedemex may significantly attenuate the morphine withdrawal symptoms in rats. The mechanism of this effect may be related to adjusting the contents of cAMP and cGMP in some brain regions.</p>