抗RSV脱氧核酶经鼻内给药后在小鼠体内脏器生物分布研究

Biodistribution of Deoxyribozyme Targeting RSV after Drug was Administrated by Intranasal Instillation in Mice

目的探讨抗RSV脱氧核酶(DZ)经鼻内给药后在小鼠体内脏器的生物学分布。方法合成互补于RSV N基因的基因组转录起始序列的DZ1133:5’TGG GGC AAA GGC TAG CTA CAA CGA ACA AAG ATG 3,’5’端和3’端的2-3个碱基进行硫代修饰,3’端连接一个胆固醇,再进行125I标记。小鼠麻醉后鼻内给药,分别于不同时间点处死小鼠并取各脏器及血液,γ计数仪测放射性计数。结果滴鼻给药后,DZ很快进入肺部和胃肠道并有少量药物吸收入血并进入其他脏器,肺部放射性浓度仅次于胃肠道,于6小时达最高峰,为总药物放射量的15.59%,24小时仍有4.9%的药物存留肺部,其浓度远远高于其他脏器。在其他脏器中,6小时脏器放射性大小依次为肝脏〉肾脏〉心脏〉脾脏〉脑部。结论肺作为DZ治疗RSV感染的靶器官,经麻醉后鼻内给药后能够达到有效浓度,且持续较长时间,建议用药间隔为24小时。

Objective To investigate the organic distribution of specific anti - RSV DNAzyme administered by intranasal instillation in normal mice. Methods DNAzymel133 ： （5＇ TGG GGC AAA GGC TAG CTA CAA CGA ACA AAG ATG 3＇ ） targeted to RSV NS gene transcription promotor region was synthesized, the first two bases at the 5 ＇ end and the last three bases at the 3 ＇ end were substituted with phosphorothioates, an cholesterol was conjugated at the 3 ＇ end, and radiolabeled with ^125 I. The DNAzyme was administered by intranasal instillation in normal mice after anesthesia. Blood samples were collected and various organs were removed respectively at different time points. Total radioactivity in each sample was measured by γ events - per - unit - time meter. Results DNAzyme was rapidly detected in lung and gastrointestinal tract and only a small amount of the radioactivity was detected in the blood and other tissues. High radioactivity was found in the lung with a peak radioactivity （15.59% total inoculated dose） by approximately 6 hour after DNAzyme1133 intranasal instillation. The radioactivity intensity in the gastrointestinal tract was the highest, and followed with radioactivity intensity in lung, liver, kidney, heart, spleen and brain in order. The highest radioactivity （4.9% of inoculated dose） was detected in lung when compared to other tissues at 24 hours after intranasal instillation. Conclusion The lung as the organ for treatment of RSV infection may obtain effective and persistent concentration of anti - RSV DNAzyme by using intranasal inoculation. The recommended drug delivery interval is 24 hours.