Objective To study the effects of several chelating agents with different structure on the lethality and removal of cadmium.MethodMice were injected,ip,with 0.05 mmol Cd/kg(cadmium chloride)and divided into five subgroups,each group was received Na_2CaEDTA,Na_3CaDTPA,DMSA,DMPS or MeOBGDTC by intraperitoneal injection respectively at the time intervals of 0 h,0.5 h,1.0 h,2.0 h and 4.0 h after injection of CdCl_2;then recorded the mortality of each subgroup in seven days.The mice of another six subgroups were used for observing the therapeutic effect of chelators on acute cadmium poisoning.The mice received 0.005 mmol Cd/kg by ip injection daily for five consecutive days,48 hours after the last cadmium injection,the mice in each subgroups were respectively given various chelators mentioned above for five consecutive days(the controls only injected with normal saline),then determined the concentrations of cadmium in the blood,kidney and liver tissues.The rats devided into four subgroups were used for observing the therapeutic effect of chelators on subchronic cadmium poisoning.Three subgroups of poisoned rats were daily ip injected with 4.448 μmol Cd/kg,5 times per week for 4 weeks,the control group rats only received the injection of normal saline;from fifth week,two subgroups' rats were respectively given 889.
600 μmol/kg of Na_2CaEDTA or MeOBGDTC daily,5 times for one week(controls and one subgroup cadmium-administrated rats only given injection of NS);24 hours after the last injection,the cadmium levels in blood,liver and kidney tissues were determined,meanwhile,the cadmium level and the activities of ALP and NAG in urine were also determined.ResultOnly MeOBGDTC may increase mice survival rate when given with a four hour delay after cadmium injection and reduce the cadmium contents in liver and kidney of acute cadmium-poisoned mice.In addition,MeOBGDTC may also significantly decrease the cadmium levels in blood,liver and kidney tissues,increase the excretion of urinary cadmium and reduce the activities of ALP and NAG of urine in subchronically cadmium-exposed rats.ConclusionIt is suggested that MeOBGDTC would be a newer and more effective chelating agent,the reason may be related to its chemical structure more easy to enter into the cells.