目的研发一种可用于携带Mathl基因进行基因转导的基于聚酰胺胺树枝状聚合物(PAMAMDen-drimers.PAMAM)的非病毒载体,对其转导效率和安全性进行评价,为进一步在体基因治疗奠定必要的实验基础和理论依据。方法PAMAM(7代)通过加热活化和环糊精(Cyclodextrin,cD)表面修饰后,与pRK5-MathI-EGFP质粒在不同氮磷比(N/P)的情况下,浮配形成基因一载体复合物,在无血清培养条件下,对HEK-293T细胞系进行体外基因转导,对其转导效率和安全性进行评价。加热活化温度设定为60℃,时间分别为:0、6、12、24、48小时:聚酰胺胺树枝状聚合物/环糊精质量比(PAMAM/CD)分别为:(1/2,1/1,4/1,8/1和无CD);N/P分别为:l/1.2/1.5/1和10/1。通过荧光倒置显微镜观察EGFP阳性细胞并计算百分比的方法评价基因转导有效率,通过怀准MTT实验评价其安全性。结果通过60℃加热活化24小时、质量比为1/1进行环糊精表面修饰后获得的基于PAMAM的非病毒基因载体,携带pRK5-Mathl-EGFP质粒进行基因转导的效率最高,达到38.14±2.85%,同时其细胞存活率达到68.86±3.44%。结论我们获得了一种基于PAMAM的非病毒基凶载体,可高效、安全地携带Mathl进行基因转导,为其下一步进行在体基因转导研究奠定了必要的实验基础,有望未来应用于临床的聋病基因治疗。
Objective To develop a novel non-viral gene vector based on PAMAM dendrimers that is able to transduce the Mathl gene, and to evaluate its efficiency and safety. Methods PAMAM was modified by cyclodextrin with different weight ratios (1 : 2, 1 : 1, 4 : 1 or 8 : 1) after activation at 60 degree for 6, 12, 24 or 48 hours. Polyplex was formed by mixing PAMAM solutions with plasmid solution containing pRK5-Mathl-EGFP of different N/P ratios (1/1, 2/ 1, 5/1 or 10/1). Transduction was performed using HEK-239T cells under non-serum conditions. The efficiency oftransduction was evaluated using percentage of EGFP positive cells, while the safety was estimated using MTT. Results The maximum transduction efficiency (38.14 ±2.85%) was achieved, with a 68.86 ± 3.44% viability, when vectors were heated for 24 hours, with a 1 : 1 PAMAM : CD ratio and 5/1 N/P ratio. Conclusion We have developed a PAMAM dendrimers-based non-viral gene vector, which is able to efficiently and safely transduce the Mathl gene in vitro. This vector may provide a new powerful tool of ~ene therapy for deafness.