ATLA::Alternatives to Laboratory Animals

Volume 29, Number 4

Lead inhibits growth and induces apoptosis in normal rat fibroblasts.

ATLA 29, 447-459, July/August 2001

Ivo Iavicoli,¹ Giovanni Carelli,¹ Alessandro Sgambato,² Oliviero Masci,¹ Raffaele Ardito,² Achille Cittadini² and Nicoló Castellino¹

¹Institute of Occupational Health and ²Centro di Ricerche Oncologiche "Giovanni XXIII", Institute of General Pathology, School of Medicine, Catholic University of S. Cuore, Largo Francesco Vito 1, 00168 Rome, Italy

SUMMARY

The effects on normal rat fibroblasts of lead supplementation (as lead acetate) in the medium were examined. The amount of lead acetate ranged from 0.078 µM to 320 µM, at 14 concentrations. The normal level of lead in the medium was 0.060 µM, and the normal concentration of lead in the fibroblasts was 3.1 ± 0.1 ng/10⁷ cells: these represented the control conditions. On studying fibroblast proliferation and survival after incubation for 48 hours, a lead acetate dose-dependent inhibition of cell proliferation was observed, the results being shown to be significant by ANOVA (p < 0.01), and suggesting a significant dose-response relationship. Apoptosis, evaluated by quantifying cytoplasmic DNA fragments, differed significantly among the lead levels tested. The distribution in the cell cycle, evaluated by using a fluorescence-activated cell sorter, showed a dose-dependent accumulation of cells in the G0/G1 phase, with a compensatory decrease in the percentage of cells in the S phase. Moreover, the occurrence of a subdiploid peak confirmed that apoptosis was more evident when the medium was supplemented with lead acetate at concentrations of 5-20 µM. The inhibition of cell growth is probably due to a direct inhibition of cell proliferation.

Keywords: lead acetate, cell surviual, apoptosis, rat fibroblasts