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The effect of aging on the metabolic function and structure of mitochondria in Hamster oocytes
Author(s) -
simsekduran fatma,
li fang,
ford wentia,
swanson r. james,
duran hakan e,
jones howard w,
castora frank j
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.855.10
Subject(s) - hamster , oocyte , mitochondrion , mesocricetus , biology , mitochondrial dna , golden hamster , mitochondrial biogenesis , medicine , endocrinology , andrology , microbiology and biotechnology , genetics , embryo , gene
In human oocytes there is a significant variation in the pregnancy potential. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. Hamster ova resemble human oocytes in size and fertility success rate and so serve as a model for understanding the human oocyte. ATP from the oocytes of young and aging hamsters was measured by a luciferase/luciferin reaction. On average, individual hamster oocytes from young animals (91 eggs from 6 animals) contain 144 ± 9.1 fmoles of ATP (0.16 uM). There is a 21% (P = 0.01) decrease in ATP (114 ± 10.1 fmoles, 0.14 uM in concentration) in old hamsters (88 eggs from 6 animals) compared to young hamsters. RT‐ PCR was used to quantitate mtDNA in individual oocytes. This analysis indicated that there is also a decrease in mtDNA molecules per oocyte as the animal ages (11,466 ± 2,025 (young) vs 7,544 ± 2,507 (old), P= 0.07). The morphology of oocytes of young and old hamsters was examined by transmission electron microscopy. TEM indicated that mitochondrial morphology undergoes distinct changes as the hamster ages. In old hamsters, the cristae are decreased in number and length compared to those in young animals. In hamsters, the decrease in ATP levels seen in aged oocytes is correlated with a similar decrease in the number of mtDNA molecules. The consequence of these changes is a reduction of 25% in ATP concentration. Such a dramatic decrease in mitochondrial energy production could compromise normal oocyte biogenesis and contribute to the reduced pregnancy potential seen in aged mammalian oocytes.