Effect of intracerebellar microinjection of cdc2-siRNA on the coordination of mice with Niemann-Pick disease type C / 中华行为医学与脑科学杂志

ABSTRACT

Objective To observe the effect of inhibiting the abnormal activation of cdc2 gene on the coordination of mice with Niemann-Pick disease type C(NPC).Methods Recombinant adeno-associated virus(rAAV) encoding cdc2-siRNA was packaged,and then was injected into the cerebellum of 2 weeks old npc-/-mice.Footprint test and vertical screen test were performed to assess the coordination of mice at the age of 8 weeks.Purkinje cells visualized by HE staining in cerebellum were counted,and the phosphorylation of microtubule-associated protein Tau recognized by PHF-1 antibody was detected by immunoblotting technology.Results (1) Footprint test showed that the stride length in cdc2-siRNA npc-/-group((4.92±0.31)cm) was markedly longer than that in empty vector npc-/-group((4.05 ± 0.19) cm) (P＜ 0.05).(2) Vertical screen test showed that the latency to turn head upwards or reach the upper edge of the screen in cdc2-siRNA npc-/-group((26.01± 1.82) s,(50.93±1.98) s) was significantly shorter than that in the empty vector npc-/-group ((31.96± 3.47) s,(56.89 ± 2.97) s),respectively (P＜ 0.05 for all comparisons).(3) The number of Purkinje cells in cerebellum was dramatically increased in cdc2-siRNA npc-/-group(11.0±2.5) compared with the empty vector npc-/-group (5.1 ± 2.2) (P＜0.05).(4)The relative optical densities of cdc2 and phosphorylated Tau immunoreactive bands in cdc2-siRNA npc-/-group(1.42±0.22,0.95±0.31)were significantly lower than those in the empty vector npc-/-group(2.11±0.29,2.61±0.62),respectively (P＜0.05 for all comparisons).Conclusion Inhibiting the abnormal activation of cdc2 gene can improve the coordination of npc-/-mice by ameliorating Purkinje cell's loss and reducing the hyperphosphorylation of Tau in cerebellum.