title: Cobalt-induced changes in the spleen of mice from different stages of development.
abstract: Cobalt(II) accumulates in organs such as spleen, kidneys, heart, and liver. The aim of the present study was to investigate the effects of cobalt ethylenediamine tetraacetic acid (Co-EDTA) on spleen of developing mice. Pregnant BALB/c mice in late gestation were subjected to Co-EDTA treatment at daily doses of 75 or 125 mg/kg in drinking water, which continued until d 90 of the newborn pups. The newborn pups were sacrificed on d 18, 25, 30, 45, 60, and 90, which correspond to different stages of development. Spleens were excised, weighed, and processed for histological analysis. Spleen index (SI) was calculated as a ratio of spleen weight to body weight. Cobalt(II) bioaccumulation in spleen was determined using flame atomic absorption spectrometry (FAAS). Preliminary results showed that chronic treatment of mice with low- or high-dose Co-EDTA disturbed extramedullary hematopoiesis in the spleen. The number of megakaryocytes was reduced compared to controls. SI was also reduced in d 18 mice treated with low- or high-dose Co-EDTA. However, exposure to 75 mg/kg led to an increase of SI in all other experimental groups. FAAS analysis revealed significant cobalt(II) accumulation in spleen of treated mice. The Co(II) levels in spleens of d 18 mice were highest compared to other experimental groups, indicating that at this period mice are more sensitive to treatment. Exposure to cobalt-EDTA resulted in accumulation of Co(II) in spleen, altered SI, and hematopoiesis. Immature mice appear to be more sensitive to chronic treatment than adults.
authors.affiliation: Institute of Experimental Morphology, Pathology, and Anthropology With Museum, Bulgarian Academy of Sciences, Sofia, Bulgaria. ygluhcheva@hotmail.com
authors.forename: Yordanka
authors.initials: Y
authors.lastname: Gluhcheva
authors.forename: Vasil
authors.initials: V
authors.lastname: Atanasov
authors.forename: Juliana
authors.initials: J
authors.lastname: Ivanova
authors.forename: Mariana
authors.initials: M
authors.lastname: Mitewa
mesh_terms: D000818:Animals; D002452:Cell Count; D003035:Cobalt / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000008:administration & dosage; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D005260:Female; D006411:Hematopoiesis, Extramedullary / Q000187:drug effects; D007774:Lactation; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects; D008533:Megakaryocytes / Q000187:drug effects / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013154:Spleen / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development / Q000473:pathology; D014018:Tissue Distribution; D036401:Toxicity Tests, Chronic
chemical_list: D004785:Environmental Pollutants; C028222:cobalt-ethylenediamine tetraacetic acid chelate; D003035:Cobalt; D004492:Edetic Acid