Variability in DDT-induced apoptosis in Mexican indigenous populations

Abstract

Context: In previous studies, we showed that DDT and its metabolites are able to induce apoptosis of peripheral blood mononuclear cells (PBMC) “in vitro” and “in vivo”, by a mechanism involving oxidative stress.

Objective: The objective of this study was to evaluate the mechanism by which DDT induces apoptosis in PBMC in children exposed to DDT and its metabolites.

Materials and methods: Eligibility criteria included children who: (1) have lived in the selected community since birth, (2) were between 6 and 14 years of age at the time of the study, (3) had not been exposed to medicaments or tobacco smoke, and (4) had had no infectious diseases in the month prior to the study. DDT and its metabolites were quantified using gas chromatography with an electron capture detector, PBMC apoptosis was measured using the TUNEL assay, DNA damage and oxidative damage were studied using the comet assay.

Results: Apoptosis correlated to DDE exposure (p = 0.040), as previously found. DNA damage also correlated to DDT (p = 0.005) and DDE (p = 0.004) levels. However, neither exposure to DDT or DDE and oxidative damage, nor oxidative damage and apoptosis, were significantly correlated. Children living in Lacanja, Chiapas, one of the communities studied in this work, had the highest levels of exposure to DDT and its metabolites, yet had the lowest percentage of apoptosis.

Conclusion: Resistance to DDE-induced apoptosis was found in children from one community. Further studies are needed in order to understand the mechanism involved in this apoptosis resistance.

Keywords::

• DDT
• health effects
• children