Endosulfan and Cypermethrin Pesticide Mixture Induces Synergistic or Antagonistic Effects on Developmental Exposed Rats Depending on the Analyzed Behavioral or Neurochemical End Points.

Exposure to pesticides has been associated with neurodevelopmental toxicity. Usually people are exposed to mixtures of pesticides. However, most studies analyze the effects of individual pesticides. Developmental exposure to mixtures of pesticides may result in additive effects or in antagonistic or synergistic effects. The aim of this work was to compare the effects of developmental exposure of rats to cypermethrin or endosulfan with the effects of its mixture on cognitive and motor function and on some underlying mechanisms. Exposure to individual pesticides or the mixture was from gestational day 7 to postnatal day 21. We analyzed the effects, in males and females, on spatial learning and memory, associative learning, anxiety, motor coordination, and spontaneous motor activity. We also analyzed neuroinflammation and NMDA receptor subunits in hippocampus and extracellular GABA in cerebellum. Exposure to the mixture, but not to individual pesticides, impaired spatial memory in males, associative learning in females, and increased motor activity in males and females. This indicates a synergistic effect of cypermethrin and endolsufan exposure on these end points. In contrast, motor coordination was impaired by individual exposure to endosulfan or cypermethrin, associated with increased extracellular GABA in cerebellum, but these effects were prevented in rats exposed to the mixture, indicating an antagonistic effect of cypermethrin and endolsufan exposure on these end points. The results show different interaction modes (synergism or antagonism) of the pesticides, depending on the end point analyzed and the sex of the rats.

Effects of endosulfan on the immune function of erythrocytes, and potential protection by testosterone propionate.

While the immunotoxicity of endosulfan has been studied, little is known about its influence on immune function associated with erythrocytes (RBC). The aim of this study was to investigate the possible effects of endosulfan, and any possible mitigation by testosterone propionate (TP), on erythrocyte immune function in a mouse model. To this end, rosette formation [as erythrocyte C3b receptor(E-C3bR) and erythrocyte immune complexes (E-IC)], as well as measures of the erythrocyte C3b receptor rosette-forming enhancing rate (RFER; reflecting immunoenhancing factor activity) and C3b receptor rosette-forming inhibitory rate (RFIR; reflecting immunosuppressive factor activity) were performed. The effects of RBC on regulating NK cell function or T-cell adherence were also analyzed. Lastly, to begin to assess potential mechanisms by which endosulfan could impact on the measured endpoints, CD35, CD58, and CD59 expression on RBC was evaluated; expression/mRNA levels of complement receptor I-related gene/protein y (Crry) on cells/splenic tissues was also assessed. The data show that E-C3bR rosette ratios decreased, and those of E-IC increased, due to endosulfan treatment. In these hosts, RFER (i.e., immunoenhancing factor in plasma) was decreased, but RFIR (i.e., immunosuppressive factor) was unchanged.There were no clear effects from endosulfan on RBC regulatory function against NK or T-cells. Lastly, Crry mRNA levels in tissues/cells from these mice were significantly decreased; however, CD59 and CD58 expression levels were unaffected. The data also show that TP co-treatment reversed or mitigated effects of endosulfan on each endpoint, in part, by two possible mechanisms; the TP may be increasing the activity of the innate immune enhancing factor, or, an anti-oxidant effect of TP might help to protect membrane structures and increase Crry stability on the RBC.

Crry receptor and oxidative stress involved in erythrocyte immune toxicity of mice caused by endosulfan and protective effects of vitamin E.

The purpose of this research was to investigate if Vitamin E could decrease the toxic-effects of endosulfan on erythrocyte immunity and its regulating mechanism. The levels of endosulfan and Vitamin E were (in mg/kg/d), respectively, 0 and 0 (control group), 0.8 and 0 (endosulfan-only group), 0.8 and 100 (experimental group). The results showed that Vitamin E inhibited endosulfan-induced decreases in rosette ratios of erythrocyte C(3)b receptor and increases in rosette ratios of erythrocyte immune complex. Vitamin E reversed the decline tendency of erythrocytes to regulate T-lymphocyte activity and the increase tendency of erythrocyte immunosuppressive factor activity in plasma induced by endosulfan. Further, Vitamin E alleviated the decreases of CD35 mRNA levels in spleen and CD35 expression on B-lymphocyte surfaces, antagonized a decline in Crry mRNA levels. Lastly, Vitamin E reversed induced decreases in total anti-oxidation capability and increases in malondi-aldehyde and free radical levels in spleen caused by endosulfan. The results suggested that Vitamin E relieved endosulfan-induced effects on erythrocytes immunity, reversed changes in expression of erythrocyte immune factors, and antagonized oxidative stress. Vitamin E could stabilize the expression of Crry receptor by inhibiting oxidative stress, and thereby reverse the decrease of erythrocyte immunity caused by endosulfan.

Evaluation of protective effects of sulforaphane on DNA damage caused by exposure to low levels of pesticide mixture using comet assay.

The objective of the study was to evaluate the potential risk of DNA damage due to exposure to a mixture of the most widely used pesticides, namely endosulfan, chlorpyriphos and thiram at an environmentally relevant concentration (5 microM each) and the DNA protective capacity of sulforaphane (SFN) (10-30 microg/mL). DNA damage in human lymphocytes was ascertained with Single Cell Gel Electrophoresis (SCGE), also called Comet Assay. For positive control, H(2)O(2) at 100 mM was used. The pesticide mixture produced DNA damage at the concentration used in the lymphocytes. SFN was able to offer a statistically significant (P < 0.01), concentration-dependant protection to DNA damage between 10-20 microg/mL in both the pre-incubation and co-incubation strategies. The results indicate that exposure to low levels of these pesticide mixtures can induce DNA damage, and the presence of SFN in diet may reduce the incidence of genetic damage, especially in farm workers. However, it is not clear whether SFN is involved in quenching of the free radicals generated by the pesticide mixture or it is involved in DNA repair mechanism.

L-ascorbic acid ameliorates postnatal endosulfan induced testicular damage in rats.

The aim of the present study is to investigate the effect of L-ascorbic acid on postnatal exposure of endosulfan induced testis damage in the rat. Four groups of seven day old male Wistar rats were treated with 3, 6, 9 and 12 mg/kg endosulfan orally (10 pups/group), from postnatal day 7 to 60 at intervals of 24 h. For 2 more groups (n = 10/group), endosulfan (9 mg/kg and 12 mg/kg) was administered along with L-ascorbic acid (20 mg/kg). The sperm morphology, sperm count and sperm motility was analyzed in all the groups on postnatal day 70. Endosulfan significantly affected the testicular function enhancing the incidence of abnormal spermatozoa, decreasing the sperm count and sperm motility in a dose dependent manner. Abnormalities were of both head and tail and increase in their frequency was more than two-fold of the control value. Sperm count abruptly decreased in 12 mg/kg group and sperm motility decreased up to 50% of the control value. L-ascorbic acid has nullified the toxic effects of the pesticide significantly, but not to the control level. Endosulfan induces the testicular damage following postnatal exposure and L-ascorbic acid prevents the adverse effects considerably in the rat.

Antimutagenic efficacy of higher doses of vitamin C.

Vitamin C, when administered concurrently with a pesticide (endosulfan, phosphamidon or mancozeb), could significantly decrease the frequency of pesticide-induced clastogenic and mitosis-disruptive changes in the bone marrow cells of young Swiss albino mice. Of the three doses (10, 20 or 40 mg/kg b.wt./day) of the vitamin, the one which is double the human therapeutic dose (20 mg/kg b.wt./day) was most effective as an antimutagen to be followed by 40 mg and 10 mg. None of these doses of vitamin C showed any genotoxicity of their own for the parameters studied here.

Neonatal endosulfan neurotoxicity: behavioral and biochemical changes in rat pups.

Repeated administration of 0.5 mg/kg endosulfan (for 5 days a week) for 3 and 5 weeks of age, produced no significant alteration either in the binding of 3H-5HT to frontal cortical membranes or in foot-shock induced fighting behavior. However, administration of 1 mg/kg endosulfan for 5 weeks caused a significant increase in 3H-5HT binding as well as in foot shock induced aggressive behavior. The endosulfan-induced increase in aggressive behavior and increased binding of 3H-5HT were detectable even 8 days after the cessation of endosulfan treatment. Scatchard analysis revealed that exposure to endosulfan altered the affinity (KD) of the receptors without causing any significant change in maximum number of high affinity binding sites (Bmax). The endosulfan-induced fighting behavior was blocked by the pretreatment of animals with methysergide, a 5-HT blocker. These results suggest an involvement of serotonergic systems in the neonatal neurotoxicity of endosulfan.