Experimental studies on renal injury of subacute and chronic cadmium-intoxication by 31P-MR spectroscopy and 1H-MR imaging

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04670680
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Radiation science
• Research Institution: Kanagawa Medical University
• Principal Investigator: YOKOTA Hajime Kanazawa Medical University, Lecturer, 医学部, 講師 (30182695)
• Co-Investigator(Kenkyū-buntansha): TONAMI Hisao Kanazawa Medical University, A.Pr., 医学部, 助教授 (70139773) ; MITSUYA Tetsuhide Kanazawa Medical University, Tutor, 医学部, 助手 (70209815)
• Project Period (FY): 1992 – 1993
• Keywords: Cadmium / 31P-MRS / 1H-MRI / 高エネルギーリン酸代謝

Research Abstract

We undertook this study to produce rats with experimental subacute and chronic cadmium poisoning and assasiated renal damage. Renal damege in these rats were assessed by 1H-MR imaging and 31P-MR spectroscopy. The effect of subacute and chronic cadmium poisoning on the rats kidneys were evaluated by comparing the changes in renal cadmium content with respect to alterations in high energy phosphate metabolism.
1.Experimental methods of subacute cadmium poisoning groups :
Change in 31P-MR spectroscopy : Signal intensity ratios with regard to high energy phosphate metabolism were detected by 31P-MR spectroscopy. The Pi/beta-ATP and Pi/ATP ratio was reduced in the early groups and Pi/beta-ATP and (alpha-ATP-beta-ATP)/beta-ATP ratio was increased in the delad group after the initiation of administration of cadmium. The PME/PDE ratio was decreased in all groups. Decrease in intra cellular pH was noted after 21 weeks of cadmium administration. Differences in the various signal intensity ratios b ecame apparent when the cadmium content in renal tissues reached the critical concentration.
2.Experimental methods of chronic cadmium poisoning groups :
Changes in 31P-MR spectroscopy : 31P-MR spectroscopy findings with regard to changes in high energy phosphate metabolism showed that PDE in the chronic cadmium poisoning group of rats shifted more to the left than that in the control group. A comparison of the signal intensity ratio between the cadmium poisoning group and control group showed that the PME/PDE and the Pi/ATP ratios were decreased in the early group. However, there was no significant difference between the two groups with resplct to intracellular pH.
Conclusion : Reduction in renal cortical ATP content and Na-K ATP ase activity have been reported. These findings are consistent with the results of the 31P-MR spectroscopy examinations which showed change in Pi/ATP, (alpha-ATP-beta-ATP)/beta-ATP, PME/PDE, and reduction in intracellular pH.Our findings indicated that the severity of renal damage can be visually assessed by the CMR-I in 1H-MR imaging examinations. In addition, we showed that 31P-MR spectroscopy can be a sensitive detector of renal damage due to cadmium poisoning.