Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China.
Drug Alcohol Depend. 2013 Apr 1;129(1-2):82-7. doi: 10.1016/j.drugalcdep.2012.09.013. Epub 2012 Oct 11.
Abnormal macrostructural brain abnormalities in both gray matter and white matter have been reported in cigarette smokers. However, less is known about white matter microstructure in heavy cigarette smokers. In this study, we used diffusion tensor imaging (DTI) to investigate the integrity of the white matter microstructure in heavy smokers.
Thirty-four heavy smokers and 34 non-smokers participated in this study. Whole brain analysis of fractional anisotropy (FA) was performed using tract-based spatial statistics (TBSS) to detect abnormal white matter regions between groups. Volume-of-interest (VOI) analysis was used to investigate changes in diffusivity indices in the regions showing FA abnormalities. Multiple regression analysis was applied to assess the relationships between diffusion indices and smoking-related variables in heavy smokers.
Compared with non-smokers, heavy smokers had lower FA in the left anterior (i.e., the genu and rostral body) corpus callosum while exhibiting no areas of higher FA. In the affected region, FA reduction was accompanied by a significantly decreased axial diffusivity and increased radial diffusivity, which suggests that axonal damage and disrupted myelin integrity may be associated with the degraded white matter integrity in heavy smokers. Moreover, significant positive correlations were found between both radial diffusivity and mean diffusivity and the duration of regular smoking.
Our findings suggest that heavy smokers demonstrate abnormal integrity of the white matter microstructure in the anterior corpus callosum, which is related to the duration of regular smoking. In addition, our study may increase the understanding of the neurobiological basis of chronic cigarette smoking.
已有研究报道，吸烟会导致灰质和白质的宏观结构异常。然而，对于重度吸烟者的白质微观结构，人们了解较少。在这项研究中，我们使用弥散张量成像（DTI）来研究重度吸烟者白质微观结构的完整性。
34 名重度吸烟者和 34 名非吸烟者参与了这项研究。采用基于束的空间统计学（TBSS）对全脑各向异性分数（FA）进行分析，以检测组间白质异常区域。采用感兴趣区（VOI）分析来研究显示 FA 异常的区域中弥散指数的变化。多元回归分析用于评估重度吸烟者中弥散指数与吸烟相关变量之间的关系。
与非吸烟者相比，重度吸烟者左侧前（即胼胝体的膝部和体部）的 FA 值较低，而 FA 值较高的区域则没有。在受影响的区域，FA 值降低伴随着轴向弥散度的显著降低和径向弥散度的增加，这表明轴突损伤和髓鞘完整性破坏可能与重度吸烟者白质完整性的降低有关。此外，还发现径向弥散度和平均弥散度与规律吸烟的持续时间之间存在显著的正相关。
我们的研究结果表明，重度吸烟者在前胼胝体的白质微观结构完整性存在异常，这与规律吸烟的持续时间有关。此外，我们的研究可能有助于增加对慢性吸烟的神经生物学基础的理解。
