Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung, 833, Taiwan.
Department of Cardiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Mol Imaging Biol. 2020 Feb;22(1):94-104. doi: 10.1007/s11307-019-01364-z.
This study aimed to investigate the feasibility of diffusion tensor imaging (DTI) and T2-mapping to assess temporal renal damage in deoxycorticosterone acetate-salt (DOCA-salt) hypertensive rats and compare the results with histopathologic and immunohistochemical findings.
After baseline renal magnetic resonance imaging (MRI), 24 out of 30 uninephrectomized Sprague-Dawley rats with DOCA-salt-induced hypertension were divided equally into four groups. Group 1 had renal MRI at weeks 2, 4, 6, and 8, and groups 2, 3, and 4 had MRI at weeks 2, 4, and 6, respectively. The remaining 6 rats were used as sham controls. The renal cortex and outer and inner stripes of the outer medulla were examined over time using fractional anisotropy (FA), apparent diffusion coefficient (ADC), and T2-mapping, and the results were compared with baseline values. The degree of glomerular and tubular injury, endothelial cell thickening, hyaline arteriolosclerosis, macrophage infiltration, microcyst formation, and fibrosis in different zones at different time points in the DOCA-salt rats were compared with controls.
Compared with baseline values, DOCA-salt rats demonstrated a significant decrease in renal cortical FA from week 4 to week 8 (0.244 ± 0.015 vs 0.172 ± 0.014-0.150 ± 0.016, P = 0.018-0.002), corresponding to significantly more glomerular damage, arteriolosclerosis, macrophage infiltration, and fibrosis. The DOCA-salt rats had significantly increased cortical ADC and T2 values at weeks 6 and 8 (1.778 ± 0.051 × 10 mm/s vs 1.872 ± 0.058-1.917 ± 0.066 × 10 mm/s; 93.7 ± 4.9 ms vs 98.0 ± 2.9-100.7 ± 4.0 ms, respectively, all P < 0.05), consistent with excessively fluid-filled microcysts (aquaporin-2+). Despite DOCA-salt rats harbored markedly increased fibrosis in outer and inner stripes of the outer medulla at weeks 6 and 8, only nonsignificant decreases in FA were observed in comparison with the controls suggesting that only limited microstructural changes were present.
Renal cortical FA is useful for the early detection and monitoring of renal damage in DOCA-salt hypertensive rats.
本研究旨在探讨扩散张量成像（DTI）和 T2 映射评估脱氧皮质酮醋酸盐-盐（DOCA-salt）高血压大鼠肾损伤的可行性，并与组织病理学和免疫组织化学结果进行比较。
在基线肾脏磁共振成像（MRI）后，将 30 只单侧肾切除的 Sprague-Dawley 大鼠中的 24 只随机分为 4 组。第 1 组在第 2、4、6 和 8 周进行肾脏 MRI，第 2、3 和 4 组分别在第 2、4 和 6 周进行 MRI。其余 6 只大鼠作为假手术对照。随着时间的推移，使用各向异性分数（FA）、表观扩散系数（ADC）和 T2 映射对肾皮质和外髓外带和内带进行检查，并将结果与基线值进行比较。在 DOCA-salt 大鼠的不同时间点，比较不同区域肾小球和肾小管损伤、内皮细胞增厚、玻璃样小动脉硬化、巨噬细胞浸润、微囊形成和纤维化的程度，并与对照组进行比较。
与基线值相比，DOCA-salt 大鼠从第 4 周到第 8 周，肾皮质 FA 显著下降（0.244±0.015 vs 0.172±0.014-0.150±0.016，P=0.018-0.002），这与肾小球损伤、小动脉硬化、巨噬细胞浸润和纤维化明显增加相对应。DOCA-salt 大鼠在第 6 和第 8 周时皮质 ADC 和 T2 值显著增加（1.778±0.051×10 mm/s vs 1.872±0.058-1.917±0.066×10 mm/s；93.7±4.9 ms vs 98.0±2.9-100.7±4.0 ms，均 P<0.05），与过多的液体积聚的微囊（水通道蛋白-2+）一致。尽管 DOCA-salt 大鼠在第 6 和第 8 周的外髓外带的外层和内层条纹中表现出明显增加的纤维化，但与对照组相比，FA 仅观察到无显著下降，表明仅存在有限的微观结构变化。
肾皮质 FA 可用于早期检测和监测 DOCA-salt 高血压大鼠的肾损伤。
