Jang Jae-Hyung, Shea Lonnie D
Department of Chemical Engineering, University of California-Berkeley, 201 Gilman Hall, Berkeley, CA 94720-1401, USA.
J Control Release. 2006 May 1;112(1):120-8. doi: 10.1016/j.jconrel.2006.01.013. Epub 2006 Mar 10.
Plasmid-loaded microspheres can provide localized and sustained release into the target tissue, and thus have the potential to enhance the efficiency of naked DNA at promoting transgene expression. In this report, microsphere design parameters are investigated by correlating the extent and duration of transgene expression intramuscularly to the polymer molecular weight and the mass of DNA delivered. Plasmid DNA was incorporated into poly (lactide-co-glycolide) microspheres using a cryogenic double emulsion process, and microspheres were injected intramuscularly. Bolus injection of naked plasmid was used for control, which exhibited transfection of muscle cells with transgene expression that gradually decreased over time. Microspheres fabricated from low molecular weight polymer had expression levels that increased from day 1 to day 92, which subsequently decreased through day 174. Decreasing the microsphere mass delivered resulted in steady expression during the same time. However, microspheres fabricated with high molecular weight polymer had expression for only 14 days. Intramuscular injection resulted in a foreign body response to the microspheres, and these infiltrating cells adjacent were primarily transfected. This understanding of microsphere properties that determine transgene expression and the distribution of transfected cells may facilitate their application to fields such as tissue engineering or DNA vaccines.
负载质粒的微球能够在靶组织中实现局部且持续的释放，因此具有提高裸DNA促进转基因表达效率的潜力。在本报告中，通过将肌肉内转基因表达的程度和持续时间与聚合物分子量及递送的DNA质量相关联，对微球设计参数进行了研究。使用低温双乳化工艺将质粒DNA掺入聚（丙交酯-共-乙交酯）微球中，并将微球注射到肌肉内。采用裸质粒推注作为对照，其表现出肌肉细胞的转染以及转基因表达随时间逐渐降低。由低分子量聚合物制备的微球，其表达水平从第1天到第92天升高，随后在第174天下降。递送的微球质量降低导致在同一时间段内表达稳定。然而，由高分子量聚合物制备的微球仅表达14天。肌肉内注射导致对微球产生异物反应，并且相邻的这些浸润细胞主要被转染。对决定转基因表达和转染细胞分布的微球特性的这种理解，可能有助于它们在组织工程或DNA疫苗等领域的应用。
