The aim of this study was to evaluate the effect of green tea extract (GTE) on the spermatic parameters of Wistar rats, submitted or not to testicular heat shock (HS). For this, 48 animals were treated according to the experimental groups (G1: not exposed to HS and untreated; G2: exposed to HS and untreated; G3: not exposed to HS and treated with GTE; G4: exposed to HS and treated with GTE). Subgroups of rats were euthanized on days 15, 30, and 60 to recover the spermatozoa. The total motility (TM), vigor, spermatic morphology and concentration, mitochondrial membrane potential, plasma membrane integrity, and acrosome integrity (ACi) were analyzed. The TM was higher in G1 and G3 than in G2 and G4 on day 30, and higher in G4 on day 60. The overall means of TM and vigor were higher in G1 and G3 than in G2 and G4, as well as TM on day 60. For the morphology, G2 and G4 were lower than G1 and G3 on day 15, and G4 was lower than G1 and G3 on day 30. Moreover, in G1 and G3 morphology was higher on days 15 and 30, and in G4 it was lower on day 30, with the overall means being higher in G1 and G3 than in G2 and G4, as well as on days 15 and 60 compared to day 30. The overall mean of ACi, on day 30, was lower than on days 15 and 60 for all the groups. Therefore, HS is shown to be widely deleterious to the gametes, and the daily administration of 100 mg/kg green tea extract does not improve the spermatic parameters of Wistar rats, submitted or not to testicular HS, although it leads to better recovery of spermatic motility and morphology at 60 days.

Objective: This study evaluated the effects of green tea extract (GTE) on the recovery of testicular parenchyma of adult Wistar rats submitted to heat stress (HS). Methodology: Animals (n=84) were distributed and treated, according to the experimental group (G1: unstressed and untreated; G2: stressed and untreated; G3: unstressed and treated; G4: stressed and treated). Results: The overall mean of testicular weight, epithelial height and tubular diameter were lower (P<0.05) in G2 and G4, and day 60 presented a higher value (P<0.05) to the two first parameters. The gonadosomatic index and the volumes of the seminiferous epithelium were lower (P<0.05) in G2 and G4. The overall means of proper tunica volume was lower (P<0.05) on day 30. The seminiferous tubule on days 15 and 30 presented lower values (P<0.05) in G2 and G4, although with higher values (P<0.05) on day 60. The volume of lymphatic space was higher (P<0.05) in G2 and G4, being day 60 higher (P<0.05) than day 15. Greater preservation and recovery of seminiferous epithelium occurred in G4, compared to G2. Conclusion: Thus, the GTE administration is an effective way to improving tissue recovery after testicular damage, induced by short-term heat.

No abstract

Influência da temperatura sobre a função testicular[Influence of temperature on testicular function] Resumo As células da linhagem germinativa são sensíveis a ação do calor, sendo a termorregulação um fator determinante para o sucesso reprodutivo. O aumento da temperatura testicular pode ocorrer devido a fatores internos ou externos e contribui para o aumento da produção de espécies reativas de oxigênio e nitrogênio, induzindo, assim, a degeneração testicular e perda de células germinativas. Em adição, mudanças nos níveis de testosterona e de corticosteroides em animais submetidos ao estresse térmico podem ser observadas e interferem na capacidade reprodutiva dos mesmos. Por outro lado, em resposta ao calor e com finalidade protetora, há o aumento da síntese de proteínas de choque térmico (HSP). Desta forma, a quantidade e qualidade do sêmen e, consequentemente, a fertilidade são comprometidas pelo estresse térmico testicular, o que torna a realização de estudos que aprofundem o conhecimento sobre as alterações causadas indispensáveis, inclusive para a busca de terapias que preservem e reparem as funções testiculares.Palavras-chave: estresse térmico; degeneração testicular; HSPs; ROS. AbstractGerm cells are sensitive to heat, thus thermoregulation is a determinant factor for reproductive success. The increase in testicular temperature can occur due to internal or external factors and contributes to the increased production of reactive oxygen and nitrogen species, which induces testicular degeneration and loss of germ cells. Furthermore, changes in testosterone and corticosteroid levels in animals submitted to heat shock can be observed and compromises the reproductive capacity. On the other hand, in response to heat, as a protection, an increase in synthesis of heat shock proteins (HSP) is observed. Therefore, the semen quantity and quality , consequently, the fertility are compromised by high temperatures, which makes necessary studies that furthers the knowledge on the changes caused, and that search for therapies that preserve and repair the testicular functions.