Detection and Bioimaging of Nitric Oxide in Bovine Oocytes and Sperm Cells

Abstract

Mammalian gametes contain constitutive nitric oxide synthases (NOS) to synthesize nitric oxide (NO). The detection and bioimaging of NO in bovine gametes is important to determine the regulatory roles of NO during the different events of fertilization. Diaminofluoresceins, new fluorescence indicators for NO, were applied to detect the release of NO from bovine gametes. These compounds yield green fluorescent triazolofluoresceins, which provide the advantages of high specificity, sensitivity, and simplicity for the detection of NO. In this study, we mapped the expression of NOS in the bovine sperm and ova. NOS activity in sperm first appeared in the acrosome, then 60 min later in the head, middle piece, cytoplasmic droplet, and tail. Cow ova had high NO activity in the cytoplasm and in the surrounding corona cells, but not in the zona pellucida. These results show that for bovine gametes, the synthesis NO by the NOS system presents clear patterns of time and spatial distribution that may be important for the different events of fertilization.

Nitric Oxide-Donor SNAP Induces Xenopus Eggs Activation

“…Other NO donors were tested at similar concentrations (Table 2), including NOR5 and SNP, but were discarded because of (1) being respectively less potent to induce NO release (data not shown), (2) producing CN − ions production, which can have secondary effects (data not shown, see also [43], [44]), (3) the toxicity of DMSO vehicle and (4) being less cell-permeant than SNAP.…”

Nitric Oxide: Key Features in Spermatozoa

“…It has been suggested that, upon approaching and entering the cumulus oophorus, both NO and progesterone, which are synthesized by the cumulus cells [9,10,[43][44][45], provide a synergistic stimulus to mobilize stored calcium in the sperm neck/midpiece [46]. As a consequence, they can modulate flagellar activity and contribute to the hyperactivation that is vital for penetration of the oocyte vestments [47].…”

“…All three isoforms of NOS have been identified in the oviduct [7,8], oocytes, and cumulus and corona cells [9,10] of several species [7,11,12]. The expression of NOS isoforms differs during the estrous cycle in the follicles as well as in the oviduct [13].…”

Atividade do sistema óxido nítrico sintase/óxido nítrico em oócitos bovinos

“…Atividade do sistema óxido nítrico sintase/ óxido nítrico em oócitos bovinos ,1997;JABLONKA-SHARIFF et al, 1999), suínos (HATTORI et al, 2000;TAKESUE et al, 2003;TAO et al, 2004) e bovinos (REYES et al, 2004;TESFAYE et al, 2006). A ovulação e a maturação são prejudicadas pela deficiência de eNOS em camundongos sugerindo que o NO é um modulador da maturação meiótica de oócitos (JABLONKA-SHARIFF; OLSON, 1998OLSON, , 2000.…”