Study On Injury Of Kidney Caused By High Molybdenum And Its Mechanism In Mice

Objective: The transition element molybdenum (Mo) is of essential importance for(nearly) all biological systems as it is required by enzymes catalyzing diverse key reactions inthe global carbon, sulfur and nitrogen metabolism. But long-time intake high-dose ofmolybdenum, it will cause a variety of organs pathological damage and functional changes.The purpose of our work was to evaluate the effect of molybdenum exposure on renalfunction in mice.Methods: Sixty35-day-old female Kunming mice were randomly allotted to threegroups. Sodium molybdate were administrated to mice at different doses (aqueous solutionwith0mg/L Mo,200mg/L Mo,400mg/L Mo) for90d. At the end of the experiment andafter one night fasting, the mice were sacrificed by excising eyeball exsanguination understunning after being weighted. Kidneys were removed.On days30,60and90of the experiment, the weight of mice was measured. Blood wascollected via excising eyeball exsanguination at the end of the experiment, and the serum wasseparated for determining the content of creatinine, urea nitrogen, malondialdehyde (MDA)and the activity of superoxide dismutase (SOD). The weight of kidneys was measuredalso.then organ coefficient of kidneys was calculated by the weight of kidneys/the weight ofmice. Renal injury were assessed by histological pathologica. Apoptosis of renal cells werevisualized by TUNEL. Bax and Smac expression was probed with immunohistochemicalassay. MDA and activity of SOD in kidneys was determined also.Result: After60,90days of the experiment, there was a lower body weight in high-dosegroup â…¡than the other groups(P<0.05).Compared with the control group, organ coefficient of kidneys was increased, and therewere significant statistical differences between the high-dose group â…¡and the controlgroup(P<0.05).The kidneys were taken out for pathological examination Results: proximal convolutedtubule epthelical cell presented swollen in the high-dose group,obviously glomeruliatrophic,particles degeneration and empty bubble degeneration of renal tubular epithelial cellswere observed in the high-dose group â…¡. Compared with the control group, the content of creatinine in serum was significantlydecreased in the high-dose groupâ… and the high-dose group â…¡(P<0.05or P<0.01).and therewere significant statistical differences between the high-dose group â…¡and the control groupin urea nitrogen(P<0.05).Compared with the control group, Apoptosis of renal cells were significantly increased inthe high-dose groupâ… and the high-dose group â…¡(P<0.01).Compared with the control group, the activity of SOD was significantly decreased in thehigh-dose groupâ… and the high-dose group â…¡(P<0.05or P<0.01)Compared with the control group, the MDA was significantly increased in the high-dosegroup â…¡(P<0.05or P<0.01)Bax and Smac labeling was observed in the renal tubular epithelial cells in the high-dosegroupâ… and the high-dose group â…¡. In the high-dose groupâ… and the high-dose group â…¡, theexpression of Bax and Smac in tubular epithelial cells significantly increased compared withthe control group(P<0.01).Conclution: Our results suggest that high content of Mo can cause glomerularatrophy,renal tubular swell,particles degeneration and empty bubble degeneration of renaltubular epithelial cells,and it induce apoptosis in kidney by enhancing the injury of lipidperoxidation, relieving the ability to resist free radical.And the apoptosis pathway may relatedwith up-regulation of Bax and Smac.