Publications by authors named "Jose Roberto V Silva"

L-carnitine has an important role in the control of oxidative stress and lipid β-oxidation during culture and cryopreservation of ovarian follicles, oocytes and embryos. This substance balances the acetyl-CoA/CoA ratio, maintains glucose metabolism and increases energy production in mitochondria. It also plays a key role in reducing endoplasmic reticulum stress, by transferring palmitate to mitochondria or eliminating it to avoid toxicity.

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This study evaluates the levels of messenger RNA (mRNA) for eIF4E, PARN, H1FOO, cMOS, GDF9, and CCNB1 in oocytes from secondary and antral follicles at different stages of development. The effects of in vitro culture, in vitro prematuration, and in vitro maturation on the expression of these genes on oocytes were also analyzed. The results showed that mRNA levels for H1FOO, GDF9, and PARN were higher in oocytes from small, medium, and large antral follicles, respectively, than those seen in secondary follicles.

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This study aims to investigate the effect of melatonin on activation, growth and morphology of bovine primordial follicles, as well as on stromal cells density in ovarian tissues after in vitro culture. Ovarian fragments were cultured in α-MEM alone or supplemented with melatonin (250, 500, 1,000 or 2,000 pM) for a period of six days. Non-cultured and cultured tissues were processed for histological analysis; according to developmental stages, follicles were classified as primordial or growing follicles.

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Short-term storage of ovaries during their transport from the collection sites to the specialized laboratories allows the recovery of thousands of oocytes from females of high genetic value, endangered species, and companion or transgenic animals, which sometimes die unexpectedly in the field, or are ovariectomized for medical reasons. Therefore, several studies have been performed to find ideal protocols to preserve oocyte viability during ovarian tissue transport, thus ensuring the success of techniques that are performed after the storage, such as cryopreservation and/or in vitro follicle culture. To achieve this goal, some factors are essential to maintain oocyte quality, such as medium, temperature, and storage time.

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The objective of this study was to determine the effects of TNF-α and IL-1β on development and survival of bovine secondary follicle culture in vitro for 18 days. Secondary follicles (~0.2 mm) were isolated from ovarian cortex and individually cultured at 38.

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Objective: To compare conventional slow equilibrium cooling and directional freezing for cryopreservation of whole ovaries.

Design: Experimental animal study.

Setting: Academic research environment.

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This study evaluated the levels of bone morphogenetic protein receptors BMPRIB and BMPRII mRNA in goat follicles and the effects of bone morphogenetic protein-15 (BMP-15) on the in vitro development of cultured preantral follicles. Real-time polymerase chain reaction (PCR) was used to analyze the levels of BMPRIB and BMPRII mRNA in caprine preantral follicles and in small and large antral follicles. Preantral follicles (≥150 μm) were also isolated from goat ovaries and cultured for 18 days in α-MEM(+) supplemented with or without BMP-15 (10, 50, or 100 ng/ml).

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Our aim was to verify the steady-state level of epidermal growth factor (EGF) mRNA in goat follicles at various developmental stages and to investigate the influence of EGF on the survival, antrum formation and growth of secondary follicles cultured for 6 days. Primordial, primary and secondary goat follicles and small and large antral follicles were obtained to quantify EGF mRNA by real-time reverse transcription with the polymerase chain reaction. The influence of EGF and the presence or absence of follicle-stimulating hormone (FSH) on the development of secondary follicles and on mRNA expression for EGF and FSH receptor (FSH-R) was determined after 6 days of culture.

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The aims of this study were to investigate steady-state level of Kit Ligand (KL) mRNA and its effects on in vitro survival and growth of caprine preantral follicles. RT-PCR was used to analyze caprine steady-state level of KL mRNA in primordial, primary, and secondary follicles, and in small (1-3 mm) and large (3-6 mm) antral follicles. Furthermore, ovarian fragments were cultured for 1 or 7 days in Minimal Essential Medium (MEM(+)) supplemented with KL (0, 1, 10, 50, 100, or 200 ng/ml).

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