别嘌呤醇对未成熟鼠脑白质损伤保护作用的研究

Protective effects of allopurinol on white matter damag e in premature rats

目的探讨别嘌呤醇对未成熟鼠脑白质损伤的保护作用。方法将新生1日龄SD大鼠84只随机分为假手术组(Sham)(n=28)、双侧颈总动脉结扎(BCAO)组(n=28)及别嘌呤醇干预组(ALLO)(n=28),BCAO制作脑白质损伤模型。观察BCAO后7d(P7,每组各6只)和14d(P14,每组8只)脑组织病理改变及MBP免疫组化变化;RT-PCR荧光定量法检测P7(每组6只)和P14(每组8只)脑组织MBP-mRNA的表达。结果BCAO组白质改变明显,ALLO组较之明显减轻;P14平均脑室大小指数,ALLO组较(2.44±0.71)%BCAO组(3.27±0.73)%明显减小(P<0.05)。P14MBP阳性染色光密度值,BCAO组(6.60±0.68)较Sham组(9.40±0.53)明显降低(P<0.01),而ALLO组(7.10±0.18)较BCAO组明显升高(P<0.05);P7、P14MBP-mRNA拷贝数(log10),BCAO组和ALLO组均明显低于Sham组(P<0.01),而ALLO组则较BCAO组明显升高(P<0.05)。结论利用1日龄大鼠行BCAO可较好地制作早产儿脑白质损伤模型。别嘌呤醇对缺血引起的未成熟大鼠脑白质损伤具有保护作用。

Objective To investigate the protective effects of allopurinol （ALLO） on white matter damage in premature rats. Methods An animal model for white matter damage was established by bilateral carotid artery occulation （BCAO）. Eighty-four newborn SD rats （ 1 day old） were used in this study and were divided randomly into three groups [ sham surgery （Sham） ; BCAO group （BCAO） ; allopurinol-treated group （ALLO）]. Pathological changes were studied 7 days and 14 days after BCAO, respectively. Myelin basic protein （MBP） was detected by immunohistochemistry 7 days and 14 days after BCAO, respectively. MBP-mRNA expression was determined 7 days and 14 days after BCAO respectively by reverse transcription-polymerase chain reaction （RT-PCR） with fluorescent quantitative method. Results In BCAO group, mild or severe rarefaction was found in 10 cases in the corpus callosum area, especially at the cingulum. Pathological changes of white matter were found in 4 cases in internal capsule. Subeortex white matter rarefaction was found in 8 cases. The extent of white matter rarefaction in ALLO group was reduced significantly. Enlargement of bilateral ventricles was found in 6 of 8 cases in BCAO group. The average ventricle size in ALLO group（2.44 ±0. 71）% was reduced significantly as compared with that in BCAO group （ 3. 27 ± 0. 73 ） % （ P 〈 0. 05 ）. Strong MBP positive staining was found in sub-cortex, corpus callosum, hippocampus gyrus, and internal capsule of P14 sham surgery group. In BCAO group the MBP staining extent was reduced. The extent of MBP staining of ALLO group was between the other two groups. The optical density （OD） of MBP positive staining in BCAO group （6. 60 ±0. 68） was found higher than that in sham surgery group （9. 40 ± 0. 53 ）, the difference was statistically significant （ P 〈 0. 05 ）. Compared with BCAO group, OD value in ALLO group （7. 10 ±0. 18） increased significantly （P 〈0. 05）. RT-PCR data showed that MBP-mRNA copies （log10） in P7 and P14 rats of both BCAO and ALLO groups were lower than that in sham surgery group （P 〈0. 01） ;However, MBP-mRNA copies in ALLO group were higher than that in BCAO group （P 〈 0. 05）. Conclusions BCAO could be used in newborn rats （ 1 day old） to establish a premature white matter damage （WMD） animal model. Allopurinol may have a potential protective effect on premature SD rat with ischemic WMD.