PARENT SESSION
TOXICOLOGY

Monday, August 2, 2004
10:30 AM–12:30 PM
Buchanan Courtyard

(86) EFFECT OF THE HERBICIDES ATRAZINE AND FENOXAPROP-ETHYL ON THE CAPACITATION AND ACROSOMAL REACTION OF PORCINE SPERMATOZOA IN VITRO.

Fierro, Reyna¹, Maravilla-Galván, Ramiro^{1, 3}, Gómez-Arroyo, Sandra ², González-Márquez, Humberto ¹, Betancourt, Miguel ¹, ¹ Departamento de Ciencias de la Salud, México, DF, México³ Doctorado en Ciencias Biológicas, México, DF, México² Centro de Ciencias de la Atmósfera, México, DF, México

ABSTRACT- Some herbicides cause physiological alterations in animals. There is evidence of structural and functional alterations in sperm morphology and chromosome aberrations. The aim of this study was to investigate the effect of the herbicides atrazine and fenoxaprop-ethyl on the viability, capacitation and acrosomal reaction of porcine spermatozoa. The CL₅₀, CL_50/2 and CL_50/5 concentrations of both herbicides were tested. The spermatozoa were incubated with the herbicides during 4 and 4.5 hours (capacitated and reacted, respectively) at 39°C in a humid atmosphere and 5% CO₂. The acrosomal reaction was induced by adding progesterone during the last half hour of incubation. The negative control was under the same conditions, with no herbicides. Capacitation and acrosomal reaction were evaluated using the chlortetracycline stain and viability using the eosin-nigrosine stain. The experiments were done at least three times. Control values were considered as 100%. Sperm viability with both herbicides decreased significantly as concentration was increased. The CL₅₀ for atrazine was 40 M and for fenoxaprop-ethyl was 60 M. Results demonstrate that both herbicides increased the capacitated and acrosome-reacted spermatozoa respect to the control. The action of atrazine began at 8 M, the capacitated spermatozoa increased to 152-155% and reacted to 153-172% as dose increased, but it was not concentration dependant. The fenoxaprop-ethyl increased capacitation to 189-279% and acrosomal reaction to 143-200%, clearly presenting a concentration-response effect. Both compounds showed significant differences when compared to the negative control. It is possible that the increase in capacitation and acrosomal reaction is due to changes in the biophysical and physiological spermatozoa membrane properties caused by the herbicides, although their mechanism of action need further investigations. This project was partially supported by CONACyT, Mexico (37923-B).

KEY WORDS: spermatozoa, acrosome reaction, herbicides, capacitation