Protective effect of hydrogen-rich water against gentamicin-induced nephrotoxicity in rats using blood oxygenation level-dependent MR imaging.

PURPOSE: We assessed intrarenal oxygenation in gentamicin-induced nephrotoxicity (GIN) and the protective effect of hydrogen-rich water (HW) against GIN using blood oxygenation level-dependent magnetic resonance (MR) imaging. MATERIALS AND METHODS: We acquired T(2)*-weighted images (T(2)*WI) of 21 rats on Days 0, 2, 4, and 7 using a 1.5-tesla MR imaging system. The rats were divided into 3 groups of seven each: control rats had free access to standard water and no gentamicin (GM) injection; rats designated the GM group had free access to standard water and were injected with GM (80 mg/kg/day) subcutaneously for 7 days; and the third group, designated the GM+HW group, had free access to HW and were injected with GM. R(2)* (=1/T(2)*) was estimated from T(2)*WI. RESULTS: R(2)* values in the cortex were significantly decreased on Days 2, 4, and 7 compared with those on Day 0 in the GM group but not significantly changed in the control and GM+HW groups. R(2)* values in the medulla did not change significantly in any group. CONCLUSIONS: Our findings suggested reduced oxygen utility, mainly in the cortex, in gentamicin-induced nephrotoxicity and an ameliorative effect of hydrogen-rich water against GIN.

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

PURPOSE: The 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 METHODS: Apparent 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. RESULTS: In 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. CONCLUSION: BOLD 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.

Statistical parametric mapping for effects of verapamil on olfactory connections of rat brain in vivo using manganese-enhanced MR imaging.

PURPOSE: We investigated the effect of verapamil on the transport of manganese in the olfactory connections of rat brains in vivo using statistical parametric mapping and manganese-enhanced magnetic resonance (MR) imaging. METHODS: We divided 12 7-week-old male Sprague-Dawley rats into 2 groups of six and injected 10 µL of saline into the right nasal cavities of the first group and 10 µL of verapamil (2.5 mg/mL) into the other group. Twenty minutes after the initial injection, we injected 10 µL of MnCl(2) (1 mol/L) into the right nasal cavities of both groups. We obtained serial T(1)-weighted MR images before administering the verapamil or saline and at 0.5, one, 24, 48, and 72 hours and 7 days after administering the MnCl(2), spatially normalized the MR images on the rat brain atlas, and analyzed the data using voxel-based statistical comparison. RESULTS: Statistical parametric maps demonstrated the transport of manganese. Manganese ions created significant enhancement (t-score = 36.6) 24 hours after MnCl(2) administration in the group administered saline but not at the same time point in the group receiving verapamil. The extent of significantly enhanced regions peaked at 72 hours in both groups and both sides of the brain. The peak of extent in the right side brain in the group injected with saline was 70.2 mm(3) and in the group with verapamil, 92.4 mm(3). The extents in the left side were 64.0 mm(3) for the group with saline and 53.2 mm(3) for the group with verapamil. CONCLUSION: We applied statistical parametric mapping using manganese-enhanced MR imaging to demonstrate in vivo the transport of manganese in the olfactory connections of rat brains with and without verapamil and found that verapamil did affect this transport.

Using BOLD imaging to measure renal oxygenation dynamics in rats injected with diuretics.

PURPOSE: we used blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) to measure renal oxygenation dynamics in rats injected with diuretics and evaluated diuretic effect on renal oxygenation. METHODS: we performed BOLD MRI studies in 32 rats using a 1.5-tesla MR imaging system for animal experiments. We intravenously injected rats with saline (n=7), furosemide (n=7), acetazolamide (n=6), or mannitol (n=6). For controls, 6 rats were not injected with drugs. We estimated the apparent transverse relaxation rate (R(2)*) from the apparent transverse relaxation time (T(2)*)-weighted images and measured the time course of R(2)* at 4-min intervals over approximately 30 min. RESULTS: compared with preadministration values, the R(2)* value did not change significantly in either the cortex or medulla in the control and mannitol groups but decreased significantly in the saline group; the R(2)* value significantly decreased in the medulla but did not change significantly in the cortex in the furosemide group; and the R(2)* value significantly increased in the medulla and significantly decreased in the cortex in the acetazolamide group. CONCLUSION: our study results suggest that BOLD MRI is useful for evaluating the dynamics of renal oxygenation in response to various diuretics in the renal cortex and in the medulla.