The Metabolism And Embryotransportation Of Nickel After Nickel And Niti Sma Implanted In Rats

Objective: This study was to investigate Ni (nickel) metabolism and embro-trasportionafter pure metal nickel and NiTi SMA (nickel and titanium shape memory alloy) were implanted in rats.Methods: Adult female rats were divided randomly into Ni group (n=15), NiTi group(n=15), and Control group (n=15). Pure metal nickel and NiTi SMA were implanted respectively into the muscle of the right hind limbs of rats. Caged 21 days later, all female rats copulated with male breeders. The pregnant rats were anesthetized with ethyl etherone on the day 18 of gestation, and the fetuses were delivered by cesarean section. The contents of Ni in urine, feces, ect.were measured by atomic absorption spectrophotometer (SPAA).Results: (1) Compared with control group, the content of Ni in blood, kidney, urine, andfeces in Ni group were significantly higher (P<0.01), and the contents of Ni in blood and urine in NiTi group also increased (P<0.05). There is positive correlation of the contents of Ni between urine and feces (r=0.457, P<0.01). (2) Patho-change was detected in histological sections of rat kidneys in Ni group. (3) In Ni group, vs control group, the contents of Ni in maternal blood, fetuses and amniotic fluid increased (P<0.01), but in placenta, lacteal gland and milk decreased (P<0.01). In NiTi group, the content of Ni in placenta, lacteal gland and milk decreased (P<0.01). (4) In histologic section of eyes of a rat fetus in Ni group, there is a large area of retina folded near optic disc.Conclusion: (1) The study showed long term implanting of nickel and NiTi SMA could reduce the content of Ni in blood, urine, and feces increased. Ni was eliminated mainly by kidney, some by digestive tract. Ni was accumulated in and damaged the kidney. (2) Ni could crossed the placenta, appeared in fetal and amniotic. In contrary, the nickel concentration in placenta decreased when that increased high in maternal blood. For nomal rats, Ni was accumulated in lacteal gland and secreted into milk. This kind of fuction of lacteal gland might be depressed when the implanted metal induced the Ni concentrate in maternal blood increasing. (3) The study suggested that Ni be a teratogen to rat embroy, and point to the retinal as target for Ni-induced embryotoxcity.