Noninvasive Monitoring and Evaluation of the Renal Structure and Function in a Mouse Model of Unilateral Ureteral Occlusion Using Microcomputed Tomography

Abstract

Mouse unilateral ureteral occlusion (UUO) is widely used as a model of renal experimental obstructive nephropathy with interstitial fibrosis. Microcomputed tomography (micro-CT) imaging has the potential to produce quantitative images. The aim of this study was to establish standard images of micro-CT for renal anatomic and functional evaluations in a mouse model of UUO. UUO was induced in adult male mice BALB/c. In total, 27 mice were used in this study. Three mice per group (a total of 6 groups) were examined with contrast-enhanced micro-CT prior to UUO (day 0) and on days 1, 3, 5, 7, 10, and 14 after UUO. In order to determine the histopathologic correlations at each point in time, contrast-enhanced micro-CT imaging was performed in the 18 remaining mice. All animals were sacrificed, and both kidneys were harvested after the final micro-CT examination. UUO resulted in hydronephrosis and changes in the renal parenchyma. The predominant alteration was substantial changes in the hemodynamics of the renal vascular system after ureteral obstruction for 24 hours or longer, which may be resulting from increased action of vasoconstrictors versus vasodilators. The renal parenchyma was significantly reduced after 1 week, and the features of the histologic changes supported the findings of the micro-CT images. In the contralateral unobstructed kidneys, the images showed a normal structure and function and the pathohistology

3D autofluorescence imaging of hydronephrosis and renal anatomical structure using cryo-micro-optical sectioning tomography

“…The kidney length (Control: 9.10 ± 0.12 mm, UUO: 10.21 ± 0.20 mm) and APDRP (Control: 1.20 ± 0.06 mm, UUO: 2.89 ± 0.38 mm) were increased in the UUO kidneys compared with the control kidneys, while the UUO kidneys showed a significantly decreased renal parenchyma thickness (Control: 3.01 ± 0.05 mm, UUO: 2.30 ± 0.14 mm) (Figure 3 C). These thickness measurements are consistent with previous studies and are considered evidence of renal parenchymal atrophy 9 , 40 . We also measured the thickness of the four main subregions of the kidneys.…”

“…For example, compared with the control kidneys, the UUO kidneys showed a decrease in the thickness and increase in the volume of the renal parenchyma and ISOM, suggesting expansion rather than atrophy of the renal parenchyma and ISOM of the UUO kidneys in the early stage. The grading of hydronephrosis, which is of great significance for the judgment of kidney injury and the selection of a treatment plan 9 , 40 , is generally based on length measurements from 2D sections 54 , 55 . However, these measurements are greatly affected by the selected position and angle of imaging, so there is no consistent and objective grading method 40 .…”

“…Methods for imaging hydronephrosis and the renal parenchyma in model animals include in vivo imaging and ex vivo imaging. Ultrasound 7 , magnetic resonance imaging 8 , and computed tomography (CT) 9 can be used to directly observe the real-time status of the kidney in vivo . However, these methods have difficulty distinguishing cellular anatomical structures, which are limited by unsatisfactory resolution.…”