Sub-chronic Toxicity Of L-Se-methyselenocysteine To SD Rats

L-Se-methyselenocysteine as a supplement to selenium,was widely paied attention to the clinical treatment and health food.However,according to literature reports,some adverse effects would be induced after long-term high-dose of L-Se-methyselenocysteine.Objective: This oral toxicity study was given 90 days to Sprague-Dawley rats with L-Se-methyselenocysteine,and the toxic reaction of SD rats was examined to identify its toxic target organs or tissues,NOAEL(no-observed adverse effect level)/ LOAEL(lowest observed adverse effect level).Methods: 100 SD rats(4-6 weeks old)were randomly divided into control groups and low,medium,med-high and high four dose groups by their weight(20 in each group,half of the females).The control group was given 0.5% CMC,and the dose of L-Se-methyselenocysteine was given at 0.15,0.30,0.45,0.60 mg Se/kg(measured in selenium).Once a day for 90 days,and continuously observe clinical symptoms,weight and intake.Blood is collected,urine and organs are collected,and hematology,urine routines,and pathology tests are carried out.Results: Compared with the control group,(1)during the trial period,rats in the high-dose group showed symptoms such as hair loss and squealing.One week after administration,it was visible that the movement was slow,that other animals had no abnormal appearance signs,that the feces color and shape were normal,that the physiological indicators were normal and that no toxic reaction satwased;and that the average weight of the high-dose group showed significant differences(P<0.01).(3)In hematology,high-dose group platelet count(PLT),serum ALB content,total bilirubin(TBIL)showed significant differences(P<0.05),(4)low SG values in the urine of rats in high-dose groups,LEU and PRO positive results increased significantly.(5)The weight and coefficient of liver organs in the female and male 0.45 mg Se/kg or greater showed significant differences.Under the light microscope,there are obvious congestion,large-scale hepatocyte vacuole degeneration and hepatocyte structural disorder in rats exposed to 0.45 mg Se/kg or greater.Renal tubule pigmentation was present in rats exposed to 0.45 mg Se/kg or greater.Testicular atrophy in the middle and high dose groups,the number of spermatogenic cells in the seminiferous tubules was significantly reduced,and sperms in the epididymal duct were lost.Conclusion:(1)After 90 days of oral administration of L-Se-methyselenocysteine,toxicological effect were observed in SD rats exposed to 0.30 mg Se/kg.(2)The toxic target organ of L-Se-methyselenocysteine should be liver,kidney and testis.(3)The NOAEL of L-Se-methyselenocysteine was 0.30 mg Se/kg,and the LOAEL was 0.45 mg Se/kg.