Avaliação estrutural de espermatozoide caprino criopreservado, através da microscopia eletrônica de transmissão / Ultrastructural evaluation of cryopreserved caprine sperm through transmission electronic microscopy

ABSTRACT

The ultrastructure evaluation allows the analysis of the sperm cell in a subcellular proportion that is not observed in optical microscopy. Transmission electron microscopy (MET) is a tool used to determine the size and shape of inorganic and biological structures based on the interaction of electrons incident on matter. In this sense, with the use of MET, the objective was to evaluate the ultrastructural changes after the semen manipulation, mainly in the freeze-thaw process, which were not observed in tests using optical microscopy, that is, the morphological integrity of the membranes and goat sperm organelles. The evaluation took place at the Institute of Biosciences of the University of Brasília (UnB). The semen straws were thawed and washed in PBS. Then, they were centrifuged and fixed, contrasted in bloc and subjected to dehydration. The samples were placed for polymerization and ultrathin cuts were made and stored until the time of MET evaluation. In the ultrastructural analyzes by MET in the present work, no harmful actions occurred in either the control or experimental groups. The head regions (plasma membrane and acrosome) remained preserved, with no change in DNA. In conclusion, MET is especially useful tool for cell evaluation.