Resveratrol Nanospheres Preparation, Characterization And In Vitro And In Vivo Anti-glioma Effect

Objective: To characterizes nanoparticles which were prepared from biodegra–dable biocompatibility polymers loaded with Resveratrol. Resveratrol-loaded nanoparticles were prepared by a nano-precipitation method using the synthesized methoxy poly(ethylene glycol)–polycaprolactone (mPEG–PCL) as drug carrier. The morphology, size distribution, in-vitro release and efficacy were evaluated to demonstrate the advantage of drug loaded nanoparticles against malignant glioma in-vitro and in-vitro, and provide fundamental evidences for the development of this novel nano-drug delivery system.Methods: Methoxy poly(ethylene glycol)–polycaprolactone (mPEG–PCL) was synthesized by ring-opening polymerization and the nanoparticles loading Resveratrol were prepared by nano-precipitation methed. The morphological examination of the nanoparticles was conducted with transmission electron microscope (TEM),scann -ing electron microscope(SEM) and atomic force microscope (AFM). Mean diameter and zeta potential were measured by photon correlation spectroscopy (DLS). Drug loading content (DLC) and encapsulation efficiency (EE) of different drug-loaded nanoparticles were determined and calculated by high performance liquid chromate- graphy (HPLC) . In vitro release pattern of drug-loaded nanoparticles were measured with the dialysis method. In vitro cytotoxicity of drug-loaded nanoparticles against U251 glioma cells was assessed by MTT assay. In vivo glioma model were evaluated to elucidate the possible antitumor mechanism of drug-loaded nanoparticles.Results: Resveratrol loaded nanoparticles showed the nearly smoothly spherical shape and size wer leess than 100 nm. The drug loading content was nearly 20 % .In vitro release study indicated that Resveratrol could be released from the core-shell structure of polymeric nanoparticles in a sustained manner. The mouse brain tissue sections and near infrared imaging demonstrated that mPEG-PCL nanoparticles could penetrate blood-brain barrier by fluorescein (Coumarin-6,NIR-797) loaded nano- particles. In vitro cytotoxicity tests showed that both free Res and Res-loaded nanoparticles were able to kill U251 glioma cells in a dose dependent manner. The significant finding of the current study was that Res-loaded nanoparticles at lower concentration could lead to significantly higher cell death compared to equivalent dose of free Res. After co-culture of the cells with fluorescein Nanospheres, the cells could intake Nanospheres through endocytosis. Resveratrol-loaded nanoparticles could induce apoptosis in U251 glioma cells by Flow Cytometry. Animal experiments had potently demonstrated that Res-loaded nanoparticles had better antitumor activity compared with free resveratrol in-vivo. Res-loaded nanospheres could inhibit tumor proliferation through inhibiting tumor angiogenesis. Glioma cells apoptosis was induced through TUNEL staining, which further verified Res-loaded nanospheres could inhibit tumor growth.Conclusion: The construction of Nanoparticles mPEG-PCL as a vector is stable and can effectively penetrate through blood-brain barrier. Res-loaded nanospheres both showed good antitumor effects and administrated its superiority to free resveratrol in the evaluation of therapeutic efficiency in vitro and in vivo. Res-loaded nanospheres could effectively induce elevation of ROS levels, inhibit tumor angiogenesis and induce the apoptosis of tumor cells, thereby inhibiting tumor proliferation. The ability of Res-loaded nanospheres'penetrating through blood-brain barrier provided a new way for the treatment of glioma. Therefore, development of drug-loaded nanoparticles systems emerges as a novel field in the research of anticancer drugs, which merits more intensive study and reveals potential application.