Expressão do complexo de histocompatibilidade principal na espermatogênese bovina

Abstract

There are two groups of MHC class I, classical and non-classical. Few things about the non-classical MHC class I genes (MHC-Ib) and their immune function in reproduction, particularly in the male bovine reproductive system, in which MHC-Ib is expressed in the sperm and testicular tissues. The reproductive capacity of a male depends on the normal functional development spermatogenic formed from a series of transformations correlated inside the testicles. Considering the hypothesis of the presence of MHC-Ib in the male bovine reproductive system, this study aimed to asses the gene expression of MHC-Ib during bovine spermatogenesis. The collections of testicular samples were carried out in abattoirs in the city of São Luís, Maranhão, with removal of testicular parenchyma fragments of 36 animals. All samples were bilateral (left and right testicles). After histological processing the samples, it was carried out the evaluation of spermatogenesis using the scoring system devised by Johnsen, where all tubular sections were systematically evaluated and given a score of 1 to 10 according sperm production. Microscopic examination showed the range of scores between the scores 6, 7 and 8. For the molecular evaluation, testicular samples divided into three groups, according to the score, totaling 12 samples/score. The qPCR analysis of the data showed no statistically significant difference in MHC-Ib expression in testicular tissue of cattle. In this study, the minimum expression of MHC in bovine testis gives the direction to the study of other molecules that may be involved in control and cell maturation during spermatogenesis. Thus, it is necessary to carry out further research using proteins and cytokines related to the differentiation of sperm cells to the deep knowledge of the role played by those in the animal’s immunity.