The study was conducted on female and male Swiss mice with body mass of 20-30 g.
The experimental animals were administered deltamethrin in concentrations of 5
mg/kg b.m. (1/10 LD₅₀) and 25 mg/kg b.m. (1/2 LD₅₀), or
fenvalerate in the doses of 10 mg/kg b.m. (1/10 LD₅₀) and 50 mg/kg
b.m. (1/2 LD₅₀). Pyrethroids were administered intragastrically once
a day for 28 days. Parallel studies were conducted in two control groups. The
following organs were taken for histologic examinations: liver, kidney, lung,
heart and spleen. Blood was taken from the heart for hematologic tests. The
total number of erythrocytes and leukocytes, the percentage of neutrophils and
lymphocytes, as well as the level of hemoglobin and hematocrit were determined.
Deltamethrin and fenvalerate caused degenerative changes in the liver and
kidneys in Swiss mice. Changes were more intense in male mice which were
administered deltamethrin, and in female mice which received fenvalerate.
Irrespective of the dose, the pyrethroids examined stimulated erythropoiesis and
synthesis of hemoglobin in male Swiss mice, while in female mice the
administration of deltamethrin in the dose of 1/10 LD₅₀ resulted in
the suppression of erythropoiesis and hemoglobin synthesis. Both in male and
female mice, deltamethrin and fenvalerate - irrespective of the dose - caused a
general increase in the number of leukocytes.