基于DTI对白质微结构介导发病年龄和抑郁症严重程度的研究

The study of white matter micro-structures mediating onset age and the severity of depressive disorder based on DTI

目的探讨抑郁症患者发病年龄、脑白质微结构及抑郁症严重程度之间的关系以及脑白质微结构在发病年龄与抑郁症严重程度之间的作用。材料与方法本研究采用前瞻性设计。对镇江市精神卫生中心收集的60例抑郁症患者(早发性抑郁症组26例、晚发性抑郁症组34例)进行磁共振扩散张量成像(diffusion tensor imaging,DTI)扫描,并应用基于纤维束示踪的空间统计方法(tract-based spatial statistics,TBSS)进行分析。应用汉密尔顿抑郁量表(Hamilton Depression Scale,HAMD)评估抑郁症严重程度。采用两样本t检验和广义线性模型比较早发性抑郁症组和晚发性抑郁症组的白质微结构。发病年龄、差异性白质微结构、抑郁症严重程度三者的相互关系采用Pearson相关分析。采用中介效应模型探讨差异性白质微结构在发病年龄与抑郁症严重程度潜在联系中的作用。结果早发性和晚发性抑郁症组的发病年龄与抑郁症严重程度均呈显著性正相关(r=0.512,P=0.007;r=0.435,P=0.010)。与早发性抑郁症组相比,晚发性抑郁症组左侧内囊、右侧矢状层(包括下额枕束和下纵束)FA值显著降低(P<0.05)。在控制协变量后,差异仍具有统计学意义(P<0.05)。Pearson相关分析显示在控制协变量后,抑郁症患者左侧内囊、右侧矢状层(包括下额枕束和下纵束)FA值分别与发病年龄、HAMD评分呈显著性负相关(r=-0.434,P=0.001;r=-0.594,P=0.001;r=-0.565,P=0.001;r=-0.370,P=0.004)。中介效应模型显示左侧内囊FA值在发病年龄和抑郁症严重程度之间存在显著性中介效应(ab path=0.155,SE=0.055,95%CI:0.0590.276)。结论左侧内囊FA值介导了抑郁症患者发病年龄对抑郁症严重程度的影响。

Objective:To investigate the relationship among onset age,white matter(WM)micro-structures and the severity of depressive disorder and explore the effect of WM micro-structures on the association between onset age and the severity of depressive disorder.Materials and Methods:Prospective design was used in this study.Sixty depressive disorder patients(26 early-onset and 34 later-onset depressive disorder groups)collected from Zhenjiang Mental Health Center underwent DTI-MRI scanning,and analysis was performed using the tract-based spatial statistics(TBSS).The severity of depressive disorder was assessed by Hamilton Depression Rating Scale(HAMD).The WM micro-structures between the early-onset and the later-onset depressive disorder groups were compared with two-sample t-test and generalized linear models.The correlation among onset age,abnormal WM micro-structures and the severity of depressive disorder were analyzed by Pearson correlation.The mediation effect models were used to explore the influence of abnormal WM micro-structures in the potential association between onset age and the severity of depressive disorder.Results:The onset age was positively correlated with the severity of depressive disorder in the early-onset and later-onset depressive disorder groups(r=0.512,P=0.007;r=0.435,P=0.010).Compared with the early-onset depressive disorder group,FA values of the left internal capsule and right sagittal stratum including inferior fronto-occipital fasciculus and inferior longitidinal fasciculus significantly decreased in later-onset depressive disorder group(P<0.05).The differences remained statistically significant(P<0.05),even after controlling for covariates.Pearson correlation analysis showed that the FA values of the left internal capsule and right sagittal stratum including inferior fronto-occipital fasciculus and inferior longitidinal fasciculus were respectively significantly negatively correlated with onset age and HAMD scores(r=-0.434,P=0.001;r=-0.594,P=0.001;r=-0.565,P=0.001,r=-0.370,P=0.004)after controlling for covariates.The mediation effect model showed that FA values of the left internal capsule had a significant mediation effect on the association between onset age and the severity of depressive disorder(ab path=0.155,SE=0.055,95%CI:0.059—0.276).Conclusions:FA values of the left internal capsule mediated the influence of onset age on the severity of depressive disorder.