豚鼠频闪光诱导性近视和形觉剥夺性近视外侧膝状体多巴胺含量的比较

Comparison of dopamine levels in the lateral geniculate nucleus in guinea pigs with flickering light-induced and form deprivation myopia

目的观察豚鼠频闪光诱导性近视和形觉剥夺性近视模型中外侧膝状体多巴胺(DA)含量的变化,并进行对比分析,初步探讨比较不同近视模型的中枢发病机制。方法 24只普通级2周龄豚鼠随机分成3组(n=8):频闪光照(FLM)组、形觉剥夺(FDM)组、对照组,各组均饲养8周。在造模前后分别测量各组豚鼠右眼屈光度和眼轴长度,8周实验结束后采用高效液相色谱电化学检测法(HPLC-ECD)对左脑外侧膝状体DA进行定量。结果造模前,各组屈光度和眼轴长度差异无显著性(P>0.05)。造模第8周,与对照组相比,FLM组和FDM组右眼屈光度变化值(P<0.001)、眼轴长度变化值(P<0.05)差异均有显著性,提示近视建模成功。HPLC-ECD结果显示:豚鼠左脑外侧膝状体DA含量FLM组>对照组>FDM组;对照组为(37.04±1.18)pg/μL;FDM组为(24.27±3.46)pg/μL,与对照组相比差异有显著性(P=0.021);FLM组为(45.58±1.98)pg/μL,与对照组相比差异有显著性(P=0.01)。结论频闪光诱导性近视模型外侧膝状体DA含量增加,而形觉剥夺性近视模型中DA含量减少,说明DA在两种实验性近视外侧膝状体中的表达不一致,两种近视模型的发生机制可能不同。

Objective To observe the dopamine（ DA） concentrations in the lateral geniculate nucleus in guinea pigs with flickering light-induced and form deprivation myopia,and to compare and analyze the pathogenetic mechanisms in the centers of vision of these two different myopia models. Methods Twenty-four two-week-old guinea pigs were randomly assigned to three groups（ n = 8） ： flickering light-induced myopia（ FLM） group,form deprivation myopia（ FDM） group and control group. All the groups were fed for 8 weeks. The refraction and axial length（ AL） were measured before and after modeling. After eight-week modeling,the contents of dopamine in the left lateral geniculate nucleus were detected by high performance liquid chromatography with electrochemical detection（ HPLC-ECD）. Results Before modeling,no significant difference was found in refraction and AL among the three groups. After eight-week modeling,in contrast with the control group,significant differences were found in changes of both refraction（ P〈0. 001） and AL（ P〈0. 05） in the right eyes of FLM and FDM groups,indicating that the two myopic models were successfully established. The result of HPLC-ECD showed that the contents of DA in the left lateral geniculate nucleus in FLM group were significantly higher than the control group（ P = 0. 01）,while in the FDM group it was lower than the control group（ P = 0. 021）. The average contents of DA were as follows：（ 37. 04 ± 1. 18） pg/μL in the control group;（ 24. 27 ± 3. 46） pg/μL in the FDM group; and（ 45. 58 ± 1. 98） pg/μL in the FLM group. Conclusions The content of DA in the lateral geniculate nucleus is increased in FLM,while decreased in FDM,indicating that the expression of DA in LGN and the mechanisms of formation of these two experimental myopia are different.