School of Pharmacy, Federal University of Ouro Preto, Ouro Preto, Minas Gerais 35400-000, Brazil.
Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais 31270-901, Brazil.
Eur J Pharm Biopharm. 2019 Sep;142:20-30. doi: 10.1016/j.ejpb.2019.05.010. Epub 2019 May 24.
Electrospinning technique has been explored to produce nanofibers incorporated with drugs as alternative drug delivery systems for therapeutic purposes in various organs and tissues. Before such systems could potentially be used, their biocompatibility must be evaluated. In this study, dexamethasone acetate-loaded poly(ɛ-caprolactone) nanofibers (DX PCL nanofibers) were developed for targeted delivery in the vitreous cavity in the treatment of retinal diseases. Ocular biocompatibility was tested in vitro and in vivo. DX PCL nanofibers were characterized by scanning electron microscopy (SEM) and Fourier Transform InfraRed spectroscopy (FTIR) and the in vitro drug release from nanofibers was evaluated. The in vitro biocompatibility of DX PCL nanofibers was tested on both ARPE-19 and MIO-M1 cells using the cytotoxicity (MTT) test by morphological studies based on staining of the actin fibers in ARPE-19 cells and GFAP in MIO-M1 cells. The in vivo biocompatibility of DX PCL nanofibers was investigated after intravitreous injection in the rat eye, using spectral domain Optical Coherence Tomography (OCT) imaging of the retina. SEM results indicated that nanometric fibers were interconnected in a complex network, and that they were composed of polymer. FTIR showed that polymer and drug did not chemically interact after the application of the electrospinning technique. PCL nanofibers provided controlled DX release for 10 days. DX PCL nanofibers were not cytotoxic to the ocular cells, allowing for the preservation of actin fibers and GFAP in the cytoplasm of ARPE-19 and MIO-M1 cells, respectively, which are biomarkers of these ocular cell populations. DX PCL nanofibers did not affect the retinal and choroidal structures, and they did not induce abnormalities, hemorrhages, or retinal detachment, suggesting that the nanofibers were well tolerated. In eyes receiving DX PCL nanofibers, SD-OCT images were corroborated with histological analysis of neuroretina and choroid, which are ocular tissues that are extremely sensitive to toxic agents. Finally, the preservation of cone and rod photoreceptors indicated the light sensitivity of the animals. In conclusion, DX PCL nanofibers exhibited ocular biocompatibility and safety in the rodent eye and allow the release of dexamethasone. Further studies are required to appreciate the potential of these new drug delivery systems for the treatment of retinal diseases.
静电纺丝技术已被探索用于生产载药纳米纤维，作为各种器官和组织治疗目的的替代药物输送系统。在这些系统具有潜在应用之前，必须对其生物相容性进行评估。在这项研究中，制备了载醋酸地塞米松的聚（己内酯）纳米纤维（DX PCL 纳米纤维），用于在治疗视网膜疾病时靶向玻璃体腔给药。在体外和体内测试了眼部生物相容性。通过扫描电子显微镜（SEM）和傅里叶变换红外光谱（FTIR）对 DX PCL 纳米纤维进行了表征，并评估了纳米纤维的体外药物释放情况。通过基于 ARPE-19 细胞中肌动蛋白纤维和 MIO-M1 细胞中 GFAP 染色的形态学研究，使用细胞毒性（MTT）试验在 ARPE-19 和 MIO-M1 细胞上测试了 DX PCL 纳米纤维的体外生物相容性。在大鼠眼内玻璃体注射后，使用视网膜光谱域光相干断层扫描（OCT）成像研究了 DX PCL 纳米纤维的体内生物相容性。SEM 结果表明，纳米纤维相互连接形成复杂网络，并且由聚合物组成。FTIR 表明，在应用静电纺丝技术后，聚合物和药物没有发生化学相互作用。PCL 纳米纤维为 DX 提供了 10 天的控制释放。DX PCL 纳米纤维对眼部细胞没有细胞毒性，允许 ARPE-19 和 MIO-M1 细胞的细胞质中保留肌动蛋白纤维和 GFAP，这是这些眼部细胞群的生物标志物。DX PCL 纳米纤维不会影响视网膜和脉络膜结构，也不会引起异常、出血或视网膜脱离，表明纳米纤维具有良好的耐受性。在接受 DX PCL 纳米纤维的眼中，SD-OCT 图像与神经视网膜和脉络膜的组织学分析相吻合，神经视网膜和脉络膜是对毒性物质极其敏感的眼部组织。最后，保存的视锥和视杆光感受器表明动物具有光敏感性。总之，DX PCL 纳米纤维在啮齿动物眼中表现出良好的眼部生物相容性和安全性，并允许释放地塞米松。需要进一步的研究来评估这些新的药物输送系统治疗视网膜疾病的潜力。
