NR2B反义寡核苷酸对脑缺血海马CA1区NR2BmRNA表达的影响

为研究NMDA受体2B亚单位(NR2B)反义寡核苷酸(antisense oligonucleotide to NR2B,ANR2B)对短暂性脑缺血后海马CA1区NR2B mRNA表达的影响,分别向成年SD大鼠海马CA1区内立体定位注射ANR2B、NR2B正义寡核苷酸(SNR2B)、无菌生理盐水(NS),或者插针不注射(NSNO),24h后行四动脉阻断前脑缺血手术(缺血15min、再灌注24h),经心冲灌固定取脑,连续冰冻切片,原位杂交组织化学方法染色,光镜下观察各组每侧鼠脑NR2B mRNA的表达变化,并用LEICAQWin进行图像分析。结果显示,单纯缺血组海马各区的NR2B mRNA显色强度明显增加;缺血再灌组、假手术组和正常组海马CA1区内ANR2B注射点及其周围的NR2B mRNA显色明显下降;而在注射SNR2B、NS或NSNO的各组海马切片上,NR2B mRNA显色均无明显变化。结果表明ANR2B可以特异性地在体局部防止缺血后NR2B mRNA的高水平表达。

THE EFFECT OF ANTISENSE OLIGONUCLEOTIDE TO NR2B SUBUNIT ON THE EXPRESSION OF NR2B mRNA IN HIPPOCAMPAL CA1 SUBFIELD OF RAT FOLLOWING TRANSIENT CEREBRAL ISCHEMIA

To probe into the effect of antisense oligonucleotide to NR2B subunit of NMDA receptor (ANR2B) on the expression of NR2B mRNA in hippocampal CA1 subfield of rat following transient cerebral ischemia, we injected respectively the ANR2B, the sense oligonucleotide to NR2B (SNR2B), normal saline (NS) into the hippocampal CA1 subfield of the rats or inserted needle without injection (NSNO) . After 24 hours , transient cerebral ischemia of rat was induced by the four-artery occlusion (occlusion of 15 minutes and reperfusion of 24 hours). Then the rat brains were cut into serial cryo-sections after perfused-fixation via heart, the in situ hybridizations of NR2B mRNA were performed, and their staining density was measured and analyzed by LEICA QWin image processing and analysis system. The results showed that the staining density of NR2B mRNA in hippocampal CA1 subfields of ischemia group increased obviously; the staining density of NR2B mRNA in hippocampal CA1 subfield surrounding ANR2B injection site decreased markedly in ischemia group, sham operation group or normal group; while their stainings saurrounding SNR2B or NS injection sites and NSNO treatment had no observable changes. The results indicate that ANR2B can specifically and topographically prevent the overexpression of NR2B mRNA following transient cerebral ischemia.