Akihiro Kitamura

Investigation of protective effect of hydrogen-rich water against cisplatin- induced nephrotoxicity in rats using blood oxygenation level-dependent magnetic resonance imaging

PurposeThe aim of this study was to assess the mechanism of the protective effect of hydrogen-rich water (HW) against cisplatin (CP)-induced nephrotoxicity in rats using blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI).Materials and methodsApparent transverse relaxation time-weighted images (T2*WI) were acquired in 28 rats. The control group (n = 7) had free access to standard water (SW) and no CP injection. The CP group (n = 7) had free access to SW and was given a CP injection on day 0. The CP+HW group (n = 7) had free access to HW and had a CP injection. The HW group (n = 7) had free access to HW and no CP injection. The apparent transverse relaxation rate (R2*) was estimated from T2*WI.ResultsIn the CP+HW group, the R2* value in the medulla normalized by the value of the day 0 was significantly greater than that in the CP group on days 4 and 7. The creatinine and blood urea nitrogen levels in the CP group were significantly higher than those in the control, CP+HW, and HW groups.ConclusionBOLD MRI may be useful for demonstrating the change in R2* in CP-induced nephrotoxicity in rats. The changes in the CP+HW group were suspected to be due to a reduction of cytotoxic oxygen radicals.

Assessment of liver function in thioacetamide-induced rat acute liver injury using an empirical mathematical model and dynamic contrast-enhanced MRI with Gd-EOB-DTPA.

To evaluate thioacetamide (TAA)‐induced acute liver injury in rats using an empirical mathematical model (EMM) and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA).

Quantitative assessment of early experimental diabetes in rats using dynamic contrast-enhanced computed tomography.

PURPOSE To quantitatively assess the time course of changes of the renal volume and function in the early phase of streptozotocin (STZ)-induced diabetes in rats using dynamic contrast-enhanced computed tomography (DCE-CT). METHODS The DCE-CT studies were performed in 24 male Sprague-Dawley rats (n=6 for control and n=18 for STZ-treated group) on days 0, 4, 7, 11, and 14 using a multi-detector row CT. The rats of an STZ-treated group were given intraperitoneally 65mg/kg body weight of STZ on day 0, and were divided into two groups based on the blood glucose concentration on day 4 being less than 300mg/dL [STZ-treated group (L), n=8] or greater than 300mg/dL [STZ-treated group (G), n=10]. The contrast clearance per unit renal volume (K(1)) was estimated from the DCE-CT data using the Patlak model. The renal volume (V(CT)) was calculated by manually delineating the kidney on the contrast-enhanced CT image. The contrast clearance of the entire kidney (K) was obtained by K(1)xV(CT). RESULTS V(CT) in the STZ-treated group was significantly enlarged on day 4 compared to that on day 0 and continued until day 14. Although there were no significant changes in the time course of K(1) in all groups, K in the STZ-treated groups (L) and (G) significantly increased on days 7 and 4, respectively, and continued until day 14, suggesting that hyperfiltration occurs in parallel with renal volume enlargement. CONCLUSION The present method appears useful for quantitatively evaluating the time course of STZ-induced diabetes in rats, because it allows repeated and simultaneous evaluation of renal morphology and function.

Experimental verification of age-dependent cisplatin-induced nephrotoxicity in rats using dynamic contrast-enhanced computed tomography

PurposeThe aim of this study was to investigate age-dependent cisplatin-induced nephrotoxicity in rats using dynamic contrast-enhanced computed tomography (DCE-CT).Materials and methodsThe DCE-CT studies were performed in 23 rats aged 4 weeks (n = 6), 6 weeks (n = 6), 8 weeks (n = 6), and 24 weeks (n = 5) on days 0, 2, 4, and 7. The rats were given intraperitoneally cisplatin 3.6 mg/kg body weight (BW) on day 0. The contrast clearance per unit renal volume (K1) was estimated using the Patlak model, and that of the entire kidney (K) was obtained by multiplying K1 by the renal volume (V).ResultsOn day 0, the K1 value increased up to 8 weeks and dropped thereafter. The V and K values increased with age. The K value per unit BW was maximum at 4 weeks, remained relatively unchanged between 6 and 8 weeks, and dropped thereafter. The BW, K1, and K values normalized by those on day 0 became lower in old rats than in young ones, and the differences among rats of different ages became greater with days after cisplatin injection, indicating that the cisplatin-induced nephrotoxicity becomes more severe with age.ConclusionThis study demonstrated the existence of age-dependent difference in cisplatin-induced nephrotoxicity in rats.