Bannai M, Ichikawa M, Nishimura F, Nishihara M, Takahashi M
Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, 1-1-1 Bunkyo-ku, Tokyo 113, Japan.
Brain Res Brain Res Protoc. 1998 Sep;3(1):83-7. doi: 10.1016/s1385-299x(98)00027-0.
One of the problems of introducing antisense oligodeoxynucleotides (ODN) into the central nervous system (CNS) is their rapid disappearance from the target site due to their dispersion and diffusion, which results in poor uptake and/or retention in cells (M. Morris, A.B. Lucion, Antisense oligonucleotides in the study of neuroendocrine systems, J. Neuroendocrinol. 7 (1995) 493-500; S. Ogawa, H.E. Brown, H.J. Okano, D.W. Pfaff, Cellular uptake of intracerebrally administrated oligodeoxynucleotides in mouse brain, Regul. Pept. 59 (1995) 143-149) [2,5]. Recently, we adapted a new method using water-absorbent polymer (WAP; internally cross-linked starch-grafted-polyacrylates) as a carrier for antisense ODN. The polymer forms a hydro-gel after absorbing water which is chemically and biologically inert. In these studies, the polymer (powder-form) is fully swollen by physiological saline containing antisense ODN (0.2 micromol/ml) to make 80-fold volume gel. Hydro-gel (1 microliter) is injected into the target site, and water solutes are assumed to be diffused stoichiometrically into CNS from the surface of the gel. Histological studies indicate that 24 h after the injection, antisense ODN (5'biotinylated-S-oligos of 15 mer) are distributed to within 800 micrometer from the edge of the area where the gel is located and then gradually disappear from this area within days, but still remain within 300-micrometer distance 7 days later. Antisense ODN are effectively incorporated by all the cell types examined, i.e., neurons, astrocytes and microglias, and suppress the synthesis of the target protein. This method can be adapted to slow delivery of antisense ODN and other water soluble substances into the CNS.
将反义寡脱氧核苷酸（ODN）导入中枢神经系统（CNS）存在的问题之一是，由于其分散和扩散，它们会迅速从靶位点消失，这导致细胞摄取和/或保留不佳（M. 莫里斯，A.B. 卢西恩，《神经内分泌系统研究中的反义寡核苷酸》，《神经内分泌学杂志》7 (1995) 493 - 500；S. 小川，H.E. 布朗，H.J. 冈野，D.W. 普法夫，《小鼠脑中脑内注射的寡脱氧核苷酸的细胞摄取》，《调节肽》59 (1995) 143 - 149）[2,5]。最近，我们采用了一种新方法，使用吸水聚合物（WAP；内部交联的淀粉接枝聚丙烯酸酯）作为反义ODN的载体。该聚合物在吸水后形成水凝胶，其在化学和生物学上是惰性的。在这些研究中，聚合物（粉末形式）被含有反义ODN（0.2微摩尔/毫升）的生理盐水充分溶胀，制成体积增大80倍的凝胶。将水凝胶（1微升）注入靶位点，假定水溶质从凝胶表面化学计量地扩散到中枢神经系统中。组织学研究表明，注射后24小时，反义ODN（15聚体的5'生物素化-S-寡核苷酸）分布在距凝胶所在区域边缘800微米范围内，然后在数天内从该区域逐渐消失，但7天后仍保留在300微米距离内。反义ODN能被所有检测的细胞类型有效摄取，即神经元、星形胶质细胞和小胶质细胞，并抑制靶蛋白的合成。这种方法可适用于将反义ODN和其他水溶性物质缓慢递送至中枢神经系统。
