Effects of aging and calorie restriction on the global gene expression profiles of mouse testis and ovary.
BACKGROUND
The aging of reproductive organs is not only a major social issue, but of special interest in aging research. A long-standing view of 'immortal germ line versus mortal soma' poses an important question of whether the reproductive tissues age in similar ways to the somatic tissues. As a first step to understand this phenomenon, we examine global changes in gene expression patterns by DNA microarrays in ovaries and testes of C57BL/6 mice at 1, 6, 16, and 24 months of age. In addition, we compared a group of mice on ad libitum (AL) feeding with a group on lifespan-extending 40% calorie restriction (CR).


RESULTS
We found that gene expression changes occurred in aging gonads, but were generally different from those in somatic organs during aging. For example, only two functional categories of genes previously associated with aging in muscle, kidney, and brain were confirmed in ovary: genes associated with complement activation were upregulated, and genes associated with mitochondrial electron transport were downregulated. The bulk of the changes in gonads were mostly related to gonad-specific functions. Ovaries showed extensive gene expression changes with age, especially in the period when ovulation ceases (from 6 to 16 months), whereas testes showed only limited age-related changes. The same trend was seen for the effects of CR: CR-mediated reversal of age-associated gene expression changes, reported in somatic organs previously, was limited to a small number of genes in gonads. Instead, in both ovary and testis, CR caused small and mostly gonad-specific effects: suppression of ovulation in ovary and activation of testis-specific genes in testis.


CONCLUSIONS
Overall, the results are consistent with unique modes of aging and its modification by CR in testis and ovary.
Sharov
Alexei A
AA
Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA. SharovAl@grc.nia.nih.gov
Falco
Geppino
G
Piao
Yulan
Y
Poosala
Suresh
S
Becker
Kevin G
KG
Zonderman
Alan B
AB
Longo
Dan L
DL
Schlessinger
David
D
Ko
Minoru Sh
MSh
D000375:Aging / Q000235:genetics*; D000818:Animals; D031204:Caloric Restriction; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020411:Oligonucleotide Array Sequence Analysis; D010053:Ovary / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000378:metabolism / Q000502:physiology*