PON1Q192R genetic polymorphism modifies organophosphorous pesticide effects on semen quality and DNA integrity in agricultural workers from southern Mexico

Pesticide exposure, including organophosphorous (OP) insecticides, has been associated with poor semen quality, and paraoxonase (PON1), an enzyme involved in OP deactivation, may have a role on their susceptibility, due to PONI polymorphisrns. Our objective was to evaluate the role Of PON1Q192R polymorphism on the susceptibility to OP toxicity on semen quality and DNA integrity in agricultural workers. A cross-sectional study was conducted in farmers with Mayan ascendancy from southeastern Mexico chronically exposed to pesticides; mostly OR Fifty four agricultural workers (18-55 years old) were included, who provided semen and blood samples. Semen quality was evaluated according to WHO, sperm DNA damage by in situ-nick translation (NT-positive cells), PONIQ192R polymorpbism by real-time PCR and serum PONI activity by using phenylacetate and paraoxon. Two OP exposure indexes were created: ait the month of sampling and during 3 months before sampling, representing the exposure to spermatids-spermatozoa and to cells at one spermatogenic cycle, respectively. PONI 192R and 192Qallele frequencies were 0.54 and 0.46, respectively. Significant associations were found between OP exposure at the month of sampling and NTpositive cells and sperm viability in homozygote 192RR subjects, and dose-effect relationships were observed between OP exposure during 3 months before sampling and sperm quality parameters and NT-positive cells in homozygote 192RR farmers. This suggests that cells at all stages of spermatogenesis are target of OR and that there exists an interaction between OP exposure and PON1IQ192R polymorphism on these effects; farmers featuring the 192RR genotype were more susceptible to develop reproductive toxic effects by OP exposure. (c) 2008 Elsevier Inc. All rights reserved.