Delay in Ovulation and Fertilization and Asynchronous Pronuclear Development in Aged Hamsters.

Suzuki, Hiroyuki; Moriguchi, Miho; Kida, Ryoko; Moro, Yuetsu

doi:10.1262/jrd.42.15

Cited by 8 publications

(14 citation statements)

References 29 publications

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“…Similar results were obtained in the aged rats [21]. Increment of retarded embryos in the aged animals may be an indication of the less viable embryos, probably resulting from the delay of ovulation [17] and abnormal fertilization [11,12,17]. Mizoguchi and Dukelow [22] have noted that aged hamsters tend to ovulate morphologically abnormal oocytes, incidence of which was 6.9% contrasting with 0.5% in young females.…”

Section: Discussionsupporting

confidence: 53%

“…Parkening and Soderwall [12,14] have noted delayed fertilization in the majority of ova in the aged hamsters. In our previous study, a delay in the process of ovulation, a delay in the male pronuclear development and high incidence of polygyny were noticed in the aged hamsters [17]. In addition, embryos from old animals showed a developmental delay before and during implantation [10,11,13].…”

Section: Discussionmentioning

confidence: 82%

“…A total of 95 virgin females were mated at 9-12 weeks of age and randomly assigned to young (9-12 weeks of age, n=48) and aged groups (43-53 weeks of age, n=47). The females in the aged group were repeatedly mated at intervals of 10-12 weeks until examination at 43-53 weeks of age according to our previous studies [16,17]. In the evening of estrus, the females were caged with young fertile males and the day when spermatozoa were found in the vaginal smear was designated as Day 1 of pregnancy (Day 1).…”

Section: Animalsmentioning

confidence: 99%

“…Our previous studies revealed that about 25-30% of decline was observed in litter size of 43-week old hamsters as compared with young females [16] and that a reduced ability to reproduce in the aged hamster may be due to an increased proportion of abnormal ova before implantation [17]. In order to clarify the causes of embryo wastage in the aged hamster, the morphological changes of the conceptuses and uterine compartments were examined in both young and aged hamsters.…”

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confidence: 99%

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Peri-implantation Embryonic Loss and Its Related Uterine Factors in Aged Hamsters.

Suzuki

Toyokawa

1999

Journal of Reproduction and Development

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Abstract. The embryonic development and changes of the uterine tissue during pregnancy were examined morphologically to reveal causes of the age-related decline in litter size in the golden hamster. Uteri were obtained from young (9-12-week old, n=48) and aged hamsters (43-53-week old, n=47) at estrus and on Days 2 to 16 of pregnancy. Viability of conceptuses were examined in half of implants from Day 6 onwards by a dissecting microscope. The remaining implants were evaluated histologically. The number of resorbing implants was significantly larger in the aged hamsters than in the young females on Day 6 (4.4 vs. 1.2, p<0.05), although no difference was found in the overall mean number of ova ovulated (14.8 vs. 14.2, respectively). Delays in the embryonic development and uterine response were observed in all aged hamsters throughout gestation. Resorbing implants noted in the aged hamsters were accompanied with stunted decidual cells having pale cytoplasm (incomplete decidualization) and heavy infiltration of endometrial granulocytes. It is suggested that the embryonic wastage may occur much crucially during the peri-implantaion period rather than late gestational period, due to the retarded development of embryos and lessdeveloped decidualization, and that endometrial granulocytes may function in resorption of greatly retarded embryos in the aged hamsters.

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 82%

Section: Animalsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Peri-implantation Embryonic Loss and Its Related Uterine Factors in Aged Hamsters.

Suzuki

Toyokawa

1999

Journal of Reproduction and Development

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“…In aged hamsters, factors affecting the reproductive decline can include abnormalities in fertilization and early development, and deterioration in the uterine adaptability to pregnancy [4][5][6][7][8][9]. Our recent study showed that in aged hamsters embryonic wastage occurred crucially during peri-implantation period rather than later gestation, and that resorbing conceptuses were accompanied with alteration of endometrium, such as incomplete decidualization [10].…”

mentioning

confidence: 99%

Altered Surface Ultrastructure of the Uterine Epithelium in Aged Hamsters.

Suzuki

Toyokawa

1999

Journal of Reproduction and Development

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Abstract. Uterine luminal surface of the hamster was examined by scanning electron microscopy (SEM) to determine whether aging alters surface ultrastructure of the endometrium where implantation takes place. On Days 2 to 3, the epithelial cells of young hamsters were round and uniformly covered with microvilli. The cells of aged hamsters were polygonal in shape with microvilli of equal density. However, in about 15% of the aged uterine epithelium examined the cells had a reduced number of microvilli. The cellular protrusions appeared on the apical membrane in young uteri on Day 4, but fewer protrusions were observed in aged uteri on Day 5 and some of them were lost before implantation. Implantation was delayed in the aged females. These findings suggest that altered surface ultrastructure of the aged uterus may reflect age-related implantation failure.

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Aging-related Changes in <i>In Vitro</i>-matured Bovine Oocytes: Oxidative Stress, Mitochondrial Activity and ATP Content After Nuclear Maturation

et al. 2014

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The objective of this research was to clarify the aging-related changes in in vitro-matured bovine oocytes. Firstly, we examined the fertilization and embryonic development of bovine oocytes after 22 and 30–34 h of in vitro maturation (IVM). The oocytes after 30–34 h of IVM (penetrated by sperm at around 40 h after starting IVM) showed a lower developmental rate to blastocysts (P<0.01), although normal fertilization rates were similar regardless of IVM duration. In the next experiment, reactive oxygen species (ROS), mitochondrial activity and ATP content in oocytes after 20, 30 and 40 h of IVM were examined. The lowest level of ROS was found in the group subjected to 30 h of IVM. The mitochondrial activity and ATP content in the group subjected to 40 h of IVM were higher than in the group subjected to 20 h of IVM (P<0.01), and those in the group subjected to 30 h of IVM showed intermediate values. Thereafter, the mitochondrial activities at 3 days after in vitro fertilization in embryos derived from the oocytes subjected to 22 and 34 h of IVM were evaluated. In the group subjected to 34 h of IVM, high-polarized mitochondria were frequently observed at the periphery of blastomeres. The present results suggest that high mitochondrial activity observed in oocytes after prolonged IVM culture and localization of high-polarized mitochondria at the periphery of blastomeres during early embryonic development may be associated with the low developmental competence in aged bovine oocytes.

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Delay in Ovulation and Fertilization and Asynchronous Pronuclear Development in Aged Hamsters.

Cited by 8 publications

References 29 publications

Peri-implantation Embryonic Loss and Its Related Uterine Factors in Aged Hamsters.

Peri-implantation Embryonic Loss and Its Related Uterine Factors in Aged Hamsters.

Altered Surface Ultrastructure of the Uterine Epithelium in Aged Hamsters.

Aging-related Changes in <i>In Vitro</i>-matured Bovine Oocytes: Oxidative Stress, Mitochondrial Activity and ATP Content After Nuclear Maturation

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