RESUMO
The epididymis is an organ that performs all the biochemical changes responsible for sperm maturation. During ageing, histological alterations in the epididymis and decreased protein synthesis have been found. This might affect the sperm maturation process. The aim of this study was to determine if the changes in the epididymis during ageing might cause alterations in sperm maturation. Wistar rats of 3-4months old (young) and 18-21months old (old) were used. The testosterone concentration was determined and the epididymides were dissected and divided in three regions: caput, corpus, and cauda. The tissues were used for histological processing and sperm extraction. Testosterone concentration decreased 34% in the old animals compared to the young ones. The distribution of mannose, sialic acid, and N-acetylglucosamine in the glycocalyx of the sperm membrane of old animals was different from that of young animals. The same occurred with phosphatidylserine externalisation and protein phosphorylation at tyrosine residues. Epididymis histology in old animals showed tubular and cellular degeneration. Our results suggest that ageing affects maturational markers, likely due to alterations in the epididymis as a result of the testosterone decrease associated with ageing.
Assuntos
Envelhecimento/metabolismo , Epididimo/metabolismo , Maturação do Esperma/fisiologia , Espermatozoides/metabolismo , Testosterona/metabolismo , Animais , Masculino , Fosforilação , Ratos , Ratos Wistar , Tirosina/metabolismoRESUMO
OBJECTIVES: Previous studies have shown alterations in bone marrow cell proliferation in malnourished rats, during lactation. The objective of this study was to determine in vivo effects of moderate and severe malnutrition on spleen cell proliferation in 21-day-old rat pups. MATERIALS AND METHODS: Spleen cell proliferation was determined following administration of bromodeoxyuridine (BrdUrd) over a time course of 2, 4, 6 and 8 h. Incorporation of BrdUrd was detected using FITC-conjugated anti-BrdUrd monoclonal antibodies and total DNA content was detected and evaluated using propidium iodide using flow cytometry. RESULTS: Proportions of cells in S and G2 /M were reduced in the rats with moderate (MN2(nd) ) and severe (MN3(rd) ) malnutrition. BrdUrd incorporation was lower in both groups of malnourished rat. In cells of MN2nd individuals, length of G1 became shorter, while length of S-phase increased. In contrast, fraction of cells in proliferation was significantly lower in both groups of malnourished rat, with MN3rd group having lowest percentage of cell population growth. In this study, severe malnutrition did not significantly affect duration of phases of the cell cycle, although fractions of proliferating cells were dramatically reduced. CONCLUSION: Moderate malnutrition increased time of cells in DNA synthesis and time of total cell cycle and severe malnutrition reduced growth fraction of spleen cells in malnourished rats during lactation.
Assuntos
Proliferação de Células , Desnutrição/patologia , Baço/citologia , Animais , Anticorpos Monoclonais/metabolismo , Peso Corporal , Bromodesoxiuridina/administração & dosagem , Bromodesoxiuridina/metabolismo , Contagem de Células , Ciclo Celular , Feminino , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/metabolismo , Lactação , Desnutrição/metabolismo , Tamanho do Órgão , Propídio/metabolismo , Ratos , Ratos Wistar , Baço/metabolismo , Fatores de Tempo , DesmameRESUMO
Malnutrition is distributed widely throughout the world and is a particular problem in developing countries. Laboratory animals have been very useful in studying the effects of varying levels of malnutrition because non-nutritional factors that affect humans may be controlled. The objective of the present study was to determine the effects of moderate and severe malnutrition on lymphocyte proportions and activation markers of T cells in experimentally malnourished rats during lactation by flow cytometry. Lower absolute (total) and relative (%) numbers of CD3+ and CD4+ lymphocyte subpopulations were observed in moderately (second degree) and severely (third degree) malnourished rats compared with well-nourished rats (P < 0.05). Both groups of malnourished rats showed a significant decrease in the percentage of CD71+ cells at 24 h post-activation with phytohaemagglutinin (PHA). After 24 h activation of spleen cells with PHA, a lower percentage of CD25+ cells was observed in malnourished than well-nourished rats (P < 0.05). In conclusion, the results of this study indicated an altered expression of CD71 and CD25 during activation of T lymphocytes in malnourished rats and may partially explain increased susceptibility to infection associated with malnutrition. Moreover, these results demonstrated that moderate malnutrition affects the response of T lymphocytes as much as severe malnutrition.
