Title: Lipid Peroxidation, Antioxidant Enzymes Activities in Testis, and Spermatotoxicity of Rats During Short-Term Exposure to Atrazine
Abstract: Background and Significance: Atrazine is a chloro-s-triazine herbicide that has been in used worldwide for over 4 decades, particularly in the United States. Emerging data have implicated atrazine as an endocrine disruptor in mammals. However, information on its mechanism of action remain unknown. Objective: The aim of this study was to evaluate the acute effects of atrazine on the testicular oxidant/antioxidant systems and on some spermatological parameters in rats. Materials and Methods: In the study 30 inbred adult male Wistar rats of initial body weights ∼165 g were randomly divided into 3 groups with 10 animals per group, and their initial body weights were recorded along with a record of their daily feed intake. Animals of each group were treated with atrazine by gavages at a dose of 0 (control), 120, or 200 mg/kg b. wt for 7 days. At 1 day after the last day of treatment, all the animals were sacrificed by cervical dislocation and paired testes, and epididymides were dissected out quickly and washed in 1.15% KCl (ice-cold), pat dried, and the wet weight was taken in an electrical monopan balance. One of the testes (left) was fixed in Bouin's fluid for histologic evaluations and the other (right) was used for the biochemical study. Date was analyzed using the Student-t-test followed by ANOVA at P<0.05. Results: The results indicate a decrease in the terminal body weight and food consumption only in the high dose groups. Testicular and epididymal sperm number, spermatozoa viability and motility in atrazine treated groups decreased significantly. Therefore atrazine treatment provoked a significant decrease in daily spermatozoal production (expressed as number of sperm per gram testis). The induction of abnormal sperm was increased by atrazine. These effects were seen in a dose dependent manner (Table 1). Although there were no significant effects on lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activities, and H2O2 generation in the atrazine groups, glutathione (GSH) and glutathione-S-transferase (GST) activities in the testis after the last day of treatment showed a significant increase vs control (Table 2). The dose and duration of treatment was inadequate to induce derangement of the seminiferous tubules but was sufficient to disrupt spermatogenesis.Table 1Effect of short-term exposure to atrazine on spermatologic parameters.ParametersControl120 mg/kg body wt.200 mg/kg body wt.Motility (%)83 ± 2.74aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.56 ± 5.48bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.44 ± 5.37cDifferent letters within the same row indicate significant (P<0.05) difference among the groups.TSN (×106/g testis)79.4 ± 1.34aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.51 ± 1bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.48.4 ± 3.58cDifferent letters within the same row indicate significant (P<0.05) difference among the groups.ESN (×106/mL)135.34 ± 5.46aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.106.65 ± 6.32bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.98.7 ± 4.81cDifferent letters within the same row indicate significant (P<0.05) difference among the groups.Viability (%)92.6 ± 5.13aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.86 ± 6.52bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.84 ± 9.62bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.Abnormal sperm (%)5.44 ± 1.08aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.9.3 ± 0.52bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.12.47 ± 1.88cDifferent letters within the same row indicate significant (P<0.05) difference among the groups.DSP (×107/g testicular parenchyma)1.47 ± 0.17aDifferent letters within the same row indicate significant (P<0.05) difference among the groups.1.32 ± 0.1bDifferent letters within the same row indicate significant (P<0.05) difference among the groups.1.13 ± 0.14cDifferent letters within the same row indicate significant (P<0.05) difference among the groups.Note: Values are mean ± SD of 10 animals per group. DSP = daily spermatozoal production; ESN = epididymal sperm number; TSN = testicular sperm number.a,b,c Different letters within the same row indicate significant (P<0.05) difference among the groups. Open table in a new tab Table 2Mean food intake and biochemical parameters of atrazine treated rats.ParameterControl120 mg/kg body wt.200 mg/kg body wt.Malondialdehyde (μmol/g tissue)21.43 ± 4.5123.4 ± 3.2724.72 ± 4.63Superoxide dismutase (nmol epinephrine oxidized/min/mg protein)23.39 ± 9.121.53 ± 9.620.22 ± 5.94Catalase (μmol H2O2 consumed/min/mg protein)340.51 ± 27.86337.3 ± 28.8326.63 ± 18.33GSH (μg GSH/mL/mg protein)4.33 ± 1.315.41 ± 1.25cVersus atrazine 200 mg/body wt.7.29 ± 1.63dVersus control (P<0.05).GST (μmol GSH-CDNB conjugate formed/min/mg protein)0.97 ± 0.141.34 ± 0.86cVersus atrazine 200 mg/body wt.3.04 ± 1.12dVersus control (P<0.05).H2O2 generation (μmol H2O2/min/mg protein)10.15 ± 6.110.24 ± 2.4210.46 ± 1.26Final body weight (g)161.25 ± 25.76aSignificant difference (P<0.05).153 ± 25.72133 ± 21.05bSignificant difference (P<0.05).Food intake (g/day)231 ± 22.47216 ± 15.57cVersus atrazine 200 mg/body wt.184.65 ± 26.43dVersus control (P<0.05).Note: Values represent mean ± SD of 10 testes/group. GSH = glutathione; GST = glutathione-S-transferase.a,b Significant difference (P<0.05).c Versus atrazine 200 mg/body wt.d Versus control (P<0.05). Open table in a new tab Note: Values are mean ± SD of 10 animals per group. DSP = daily spermatozoal production; ESN = epididymal sperm number; TSN = testicular sperm number. Note: Values represent mean ± SD of 10 testes/group. GSH = glutathione; GST = glutathione-S-transferase. Conclusion: Our study has added the information that oral atrazine exposure attributes to alterations in spermatologic parameters without significant effects on the parameters of oxidative stress. Possibly atrazine may not have a direct effect on the seminiferous epithelium. Furthermore, it seems that the conjugation of atrazine to GSH appears more responsive to the metabolism of atrazine than by the testicular oxidative system. This may be secondarily related to the restricted food intake.