Dados da dissertação de mestrado

The cylindrospermopsin (CYN) - a cyanotoxin (toxin produced by cyanobacteria) - is a potent inhibitor of protein synthesis, able to cause serious damage to various organs It has the potential role of endocrine disruptor, able to inhibit the synthesis of progesterone and change the estrous cycle of females. Therefore, to analyze possible effects on males, the aim of this study was to evaluate the subchronic effect of CYN in murine male reproductive system. A subchronic assay was performed with 20 mice, with approved protocol (CEUA122/14). The animals were divided into four groups: 1, 2, 3 and control group (5 animals / group). The intraperitoneal injections at a dose of 20 μg of CYN / kg body weight occurred at the beginning of the experiment for all groups. Group 1 was euthanized and the groups 2 and 3 were re-injected 7 days after exposure to the initial dose. On the 14th day the group 2 euthanasia and reinjection of group 3 was realized. The group 3 was re-injected at 21th day and at 28th day occurred the euthanasia. Like Group 3, the control group remained until the 28th day receiving weekly injections only vehicle, ultra pure water solution (MilliQ). In the days of euthanasia (7th, 14th and 28th), blood was collected and tissues (liver, pituitary, testis and epididymis) collected and weighed. Statistical analyzes were performed with the simple analysis of variance (One way ANOVA) followed by Tukey's multiple comparison test were chosen. Our results indicate that one or two weekly low dose of CYN (groups 1 and 2) caused a significant increase in testosterone levels and there is a significant increase of sperm quantity in group 3. On the other hand, the toxin did not cause changes in the weights of the tissues as well as in the expression of pituitary (LHb and FSHb) and testicular (LHcgr, StAR and CYP11A1) genes. The changes observed have shown significant interference in the male reproductive system, although it is not known the mechanism whereby causes changes. Therefore, further studies are needed to understand the role of CYN as an endocrine disruptor.