Efeitos do inseticida endossulfam sobre a morfologia e a morfometria testicular em morcegos frugívoros Artibeus lituratus (OLFERS, 1818) / Effects of the endosulfan on the testicular morphology and morphometry in fruit bats Artibeus lituratus (OLFERS, 1818)
Michele Oliveira Santos
DATA DE PUBLICAÇÃO
Large amounts of agricultural chemicals are discharged into the environment in Brazil. These pesticides are often used to destroy or impair the activity of organisms that attack crops. There are some reports in the literature concerning the decline of many wildlife populations as a result of contamination of their habitats by pesticides. One of the putative affected species is the fruit bat Artibeus lituratus, which are efficient seed dispersers along tropical and subtropical regions, where they occur, helping in the balance of ecosystems in these regions. Furthermore, they can provide valuable insights on the patterns of contamination in mammals in general, because they are highly mobile and occupy a privileged position on the food chain. Endosulfan is a widely used insecticide and acaricide, and acts by contact and ingestion. Despite its broad spectrum of action, endosulfan is well tolerated by a number of beneficial insects and has been proven effective against a wide variety of pests. Nonetheless, studies showing its effect on the physiology of bats are needed, especially on the reproductive biology of these animals. The aim of this study was to evaluate the toxicity of the insecticide endosulfan on testicular morphology and morphometry in fruit bats A. lituratus. Twenty-six A. lituratus adult male bats were captured from Atlantic Forest remnants in the region of Viçosa, State of Minas Gerais, Brazil, using mist nets and kept in cages in an Animal House at the Museum of Zoology, Department of Animal Biology of UFV. They were randomly divided into 4 groups: 1) control (GC): receiving papaya without endosulfan; 2) spreader (GES): receiving papaya exposed to adhesive spreader Wil Fix, in a solution with concentration 0.015 g / L; 3) endosulfan ( GE I): receiving papaya exposed to an endosulfan solution with a concentration of 1.05 g / L; and 4) endosulfan (GE II): receiving papaya exposed to an endosulfan solution with a concentration of 2.1 g / L. Treatment lasted 35 days, after that, animals were euthanized and the testes were collected, weighed and then processed for routine histology in glycol methacrylate. Testis morphometry and stereology of both tubular and intertubular compartments were performed using images obtained from histological slides. The parameters evaluated were: seminiferous tubules diameter and seminiferous epithelium height, the volumetric proportion of the testicular parenchyma components and intertubular compartment, the total length of seminiferous tubules and the gonadosomatic (GSI), leydigosomatic (ILS) and tubulossomatic (ITS) indices, plus, the Leydig cell volume. All the measurements were performed using the software Image-Pro Plus 4.5. Data was analyzed using ANOVA and Student-Newman-Keuls test to compare means, level of significance was 5%. The results on the biometric parameters of body and testes were not significantly different among groups. Weight of albuginea was increased in the group treated with the highest dose (GE II) compared to control and GES. We found a lower percentage of Leydig cells in the animals of GE II in comparison to the other groups. The lymphatic space was greater in the groups GES, GE I and GE II, compared to control. These groups GES, GE I and GE II showed an increase in the percentage of the nucleus and a reduction in the cytoplasm of Leydig cells. There was a reduction in volume of Leydig cell cytoplasm in GE II. There were no differences in the number cell of Leydig cells per testis and per gram of testis, also in the Leydigosomatic index. The lack of changes in tubular and intertubular spaces in A. lituratus indicates that the endosulfan, at the concentrations used and the duration of this experiment, did not interfere with spermatogenic patterns of this bat species.
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