Effect of chronic lead on the haematology, blood glutathione and bone marrow non-haeme iron of dogs.

Ten clinically normal male beagle dogs were used in the study. Two dogs served as control, 4 received 2 mg lead/kg daily and 4 received 5 mg lead/kg/daily. Lead was administered for 13 weeks, after which one-half of each experimental group was treated with calcium ethylene diaminetetraacetate (CaEDTA) for 5 days. All animals were then monitored for another 4 weeks. Blood lead levels, haematology, blood glutathione concentration, and the number of bone marrow cells with stainable iron granules were measured weekly during the 18-week experimental period. Clinical signs of poisoning were observed only in one dog in the high dose group after 6 weeks. The signed included emaciation, anorexia, muscular weakness, evidence of abdominal pain and depression. These signs were reversed with cessation of lead dosing and CaEDTA treatment. Blood lead levels and the number of marrow cells with non-haeme iron increased in both lead-dosed groups; nucleated red blood cells increased only in high lead dosed group. There was a trend for an increased packed cell volume in all groups; however, the high lead dosed group did not increase as fast. No significant changes were observed in blood glutathione concentration and in other haematologic parameters. There were no differences in the parameters studied between the dogs treated with CaEDTA and those not so treated. Blood lead levels and the number of nucleated red blood cells decreased after cessation of lead administration and the number of marrow cells with iron also tended to decrease after lead removal.