Conteúdo de peptídeos e avaliação morfofisiológica dos espermatozóides do epidídimo e ejaculado de bovinos Peptides content and morphophisiological evaluation of epididymis and ejaculated sperm in bovine

Objetivou-se com este estudo a identificação de alguns fatores protéicos envolvidos na qualidade funcional dos espermatozóides epididimais (SPZEP) e ejaculados (SPZEJ) de bovinos. Foram avaliadas as características morfofisiológicas e analisado o conteúdo peptídico destas estruturas de 11 animais mestiços Nelore, de 24 a 30 meses de idade. As avaliações morfofisiológicas foram motilidade progressiva (MOT, %), vigor, patologias espermáticas, integridade acrossômica e da cromatina. Foi observado que, os SPZEJ, na média, apresentaram MOT maior do que os SPZEP, 72,3 e 46,4%, respectivamente. Considerando as patologias espermáticas, taxas de defeitos maiores (DEFMAI), menores (DEFMEN) e totais (DEFTOT), houve diferença significativa entre as taxas dos DEFMEN e DEFTOT dos SPZEP e SPZEJ, sendo, em média, 91,1 e 8,5% e 95,4 e 11,8%, respectivamente. As taxas dos DEFMEN e DEFTOT dos SPZEP foram maiores em função da presença de espermatozóides com gotas citoplasmáticas distais. A análise das protéinas dos SPZEP e SPZEJ foi realizada por espectrometria de massa, método MALDI-TOF (matrix -assisted laser desorption/ionization - time of flight), e revelou presença de peptídeos de massa molecular variando de 1,1 a 26,3 kDa nos SPZEJ e de 1,1 a 11,6 kDa nos SPZEP. Foram identificados peptídeos de 10,6 e 13,4 kDa somente nos SPZEJ e de 6,8 kDa somente nos SPZEP. Foi observada relação do peptídeo de massa molecular de 7,4 kDa dos SPZEP e de 4,7 kDa dos SPZEJ, com a MOT Ê 80%, destas estruturas. Os resultados sugerem o envolvimento destes peptídeos nos processos funcionais das células espermáticas do epidídimo e ejaculado. O estudo utilizou o método MALDI/TOF para espectrômetro de massa, para identificar peptídeos em espermatozóides do epidídimo de bovinos, pela primeira vez no País.<br>The objective of the study was to identify some protein factors involved in bovine epididymis (SPZEP) and ejaculated (SPZEJ) sperm functional quality. With this propose, epididymis and ejaculated sperm of 11 Nellore crossbreed animals, 24 to 30 month of age, was evaluated for morphophisyological characteristics and analyzed for the peptides content. The morphophisyological characteristics consisted of progressive motility (MOT, %), velocity, sperm pathologies, and acrosome and chromatin integrity. These evaluations showed that the mean values of the SPZEJ were higher than of SPZEP, 72.3 and 46.4%, respectively. The considered sperm pathologies were the major, minor and total abnormalities. It was observed a significant difference between the means values of the minor and total abnormalities of epididymis and ejaculated sperm, 91.1 and 8.5% and 95.4 and 11.8%, respectively. These differences were caused by the presence of sperm with distal citoplasmatic droplets. The analysis of the protein of epididymis and ejaculated sperm was realized by mass spectrometer, MALDI-TOF method (matrix-assisted laser desorption/ionization-time of flight). The method identified low molecular mass proteins, i.e. peptides. The analysis of SPZEJ showed peptides ranging from 1.1 to 26.3 kDa and SPZEP from 1.1 to 11.6 kDa. Some peptides, such as 10.6 and 13.4 kDa, were found only in ejaculated sperm, and the other, such as 6.8 kDa, only in epididymis. A relationship was observed between the 7.4 kDa SPZEP and 4.7 kDa SPZEJ peptides and sperm with Ê 80% motility. These last results suggested the participation of these peptides in the functional processes of spermatic cells. This study used for the first time in this country the MALDI/TOF mass spectrometer method to identify peptides in bovine epididimal sperm.