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Cytochemical study on mouse spermatozoa chromatin during epididymal maturation and during in vivo and in vitro capacitation
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Cytochemical quantitative determination on LDH and cytochrome oxidase activities in fresh and frozen-stored bull spermatozoa during in vitro capacitation
No full textDosaggio microdensitometrico dell'attività glucoso 6-fosfato deidrogenasica in spermatozoi di topo e di coniglio nel corso della perossidazione lipidica spontanea.
No full textpoichè il glutatione, in qualità di substrato per il sistema enzimatico glutation/perossidati/reduttasi, garantisce un'efficace difesa nei riguardi dei danni provocati dalla perossidazione lipidica, sono stati studiati spermatozoi di topo (ad elevato contenuto in glutatione) e di coniglio (a basso contenuto in glutatione) incubati in media che consentono il realizzarsi di fenomeni di perossidazione lipidica. le indagini citochimiche quantitative sull'attività G6PDH condotte con metodo microdensitometrico hanno messo in luce l'esistenza, in entrambe le specie, di una correlazione dell'intensità di produzione di NADPH attraverso lo shunt dei pentosi con il contenuto intracellulare in glutatione e con il grado di perossidazione lipidic
Effects of lipid peroxidation on chromatin in rabbit and mouse spermatozoa: a cytochemical approach
No full textTo extend present knowledge on the possible interactions between lipid peroxidation and chromatin, we studied rabbit and mouse spermatozoa during spontaneous lipid peroxidation. Epididymal spermatozoa were aerobically incubated in high sodium or high potassium media to obtain spontaneous lipid peroxidation in the absence of added promoters. Quantitative cytochemical assays were performed in situ, in individual spermatozoa processed by Feulgen reaction and Gallocyanin-chrome alum (GCA) staining. Our findings show that in both species examined, the spermatozoa chromatin undergoes destabilization associated with marked alterations of the physico-chemical state of the DNA-protein complex. The decrease of Feulgen and GCA-positive material may be explained by DNA damage and implies the release from the nucleus of DNA fragments. Moreover, our data support the idea that during spontaneous lipid peroxidation, the spermatozoa chromatin undergoes destabilization sometimes correlated with increased acid lability of the DNA-protein complex. There are differences in the two species, probably correlated with differences in major protective enzymatic systems against cell damage by autoxidation and, especially, against different kinds of oxygen radicals responsible for initiation of lipid peroxidation
Studio citochimico quanti-qualitativo sugli effetti della perossidazione lipidica spontanea sullo stato fisico-chimico della cromatina.
No full textAllo scopo di approfondire lo studio sulle possibili interazioni fra radicali liberi e prodotti della perossidazione lipidica ed il complesso DNA-proteine, è stata condotta, con metodo microdensitometrico, un'indagine citochimica sulla cromatina dello spermatozoo, cellula particolarmente vulnerabile nei riguardi di fenomeni di autossidazion
Fas ligand in bull ejaculated spermatozoa : a quantitative immunocytochemical study
No full textApoptosis, or programmed cell death, provides a way to remove redundant cells at
the end of their lifespan and thus acts as a homeostatic mechanism, maintaining the
correct number of cells in the body by balancing their production and death. In the
testis, this process seemed to play a pivotal role in spermatogenesis. It is generally
accepted that Sertoli cells control the germ cell population through one of the bestknown
apoptotic pathways, the Fas/Fas L paracrine signal transduction system, in
which a Fas ligand (Fas L) expressed by Sertoli cells induces apoptosis when it binds
with its receptor, Fas, expressed by the germ cells.
Recently, we demonstrated the presence of Fas antigen in normal ejaculated
spermatozoa from fertile bulls and suggested that this molecule might have a nonapoptotic,
defensive role against injuries, especially oxidative stress. We have now
investigated whether bull mature, fertile spermatozoa express not only the Fas
receptor but also its natural ligand Fas L. Our results indicate that the whole sperm
population expresses Fas L.
We suggest that Fas L in bull spermatozoa, like in murine spermatozoa, might be
able to kill activated lymphocytes and protect the male gamete from damage by the
self-immune system or the cytotoxic activity of leukocytes in the female genital
tract
Effetto della perossidazione lipidica spontanea sulle attività citocromo ossidasica e lattato deidrogenasica in spermatozoi di coniglio
No full textMolti dati esistenti in letteratura depongono a favore dell'ipotesi che la maggior parte degli effetti negativi che l'ambiente aerobico esercita sul gamete maschile siano attribuibili a fenomeni di perossidazione lipidica; molti degli eventi biologici correlati ai processi di invecchiamento dello spermatozoo possono essere quindi ridiscussi alla luce della teoria radicalica della senescenza cellular
Microphotometric study of glucose-6-phosphate dehydrogenase activity in epididymal spermatozoa during spontaneous lipid peroxidation.
No full textMammalian spermatozoa are highly sensitive to lipid peroxidation and the glutathione peroxidase/reductase system provides an effective defense against oxidative damage to different degree in different species. Rabbit spermatozoa rely on superoxide dismutase as the primary enzymatic defense against lipid peroxidation and contain only low detectable endogenous glutathione reductase activity while in mouse spermatozoa the glutathione system is the major protective enzyme against cell damage by autoxidation. We describe a cytochemical quantitative assay for glucose-6-phosphate dehydrogenase activity in rabbit and mouse spermatozoa undergoing spontaneous lipid peroxidation during in vitro incubation. Microdensitometric measurements were made by a Vickers M85a scanning microdensitometer at λ585 nm wavelength. Our findings suggest that in mouse spermatozoa, the enhanced glutathione reductase and peroxidase activities induced by the spontaneous lipid peroxidation increases NADPH production from the pentose phosphate shunt, while in rabbit spermatozoa, NADPH production is much lower
Cytochrome oxidase and lactate dehydrogenase activities in peroxidized rabbit epididymal spermatozoa.
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