Age-related changes in interstitial fibrosis and germ cell degeneration of the canine testis.

Fifty-five healthy medium-sized dogs were divided into four groups; young (1-3 years old, n = 14), adult (>3 to 6 years old, n = 12), old (>6 to 9 years old, n = 14) and senile (>9 years old, n = 15). After routine orchiectomy, testes were collected, and the degree of white streak areas on cut surfaces was subjectively assessed. Later, testicular tissue sections were stained with haematoxylin and eosin and Masson's trichrome for evaluation of germ cell degeneration and the proportion of interstitial connective tissue, respectively.

Reproductive aging in male dogs: The epididymal sperm defects and expression of androgen receptor in reproductive tissues.

The present study aimed at investigating age-related changes in epididymal sperm motility, morphology, DNA integrity and androgen receptor (AR) expression in canine reproductive tissues. Fifty-five healthy medium-sized male dogs were divided into four groups: young (1 - 3 years old, n = 14), adult (>3 - 6 years old, n = 12), old (>6 - 9 years old, n = 14) and senile (>9 years old, n = 15). After routine castration, testes, epididymides (head, body and tail) and vas deferens were collected.