Bhanmeechao Cholayuth, Srisuwatanasagul Sayamon, Ponglowhapan Suppawiwat
Department of Obstetrics, Gynaecology and Reproduction, Research unit of Obstetrics and Reproduction in Animals, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
Department of Anatomy, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
Reprod Domest Anim. 2018 Nov;53 Suppl 3:37-43. doi: 10.1111/rda.13354.
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. Semiquantitative severity scoring of germ cell degeneration and quantitative analysis of spermatogenic cells for spermatic index (SI) and Sertoli cell index (SEI) was performed. The score of white streak on cut surface area of the testes increased with age, being higher (p < 0.05) in senile dogs than other age groups; no difference was found between adult and old dogs. The proportion of testicular interstitial fibrosis was highest (p < 0.05) in senile dogs. Positive correlations between age and white streak area (rho = 0.77, p < 0.01) as well as age and interstitial fibrosis (rho = 0.63, p < 0.01) were observed. The severity of germ cell degeneration gradually increased with age and differed among age groups (p < 0.05). Age positively correlated with atrophy of seminiferous tubules (rho = 0.93, p < 0.01). The SI was lower (p < 0.05) in senile dogs compared to other age groups, and SI was not different among young, adult and old dogs. Conversely, SEI was significantly higher in senile dogs compared to young, adult and old dogs. A negative correlation between age and SI (rho = -0.69) and a positive correlation between age and SEI (rho = 0.68) were significant (p < 0.01). In conclusion, influence of age on testicular interstitial fibrosis and germ cell degeneration/depletion were pronounced in dogs over 9 years old.
55只健康的中型犬被分为四组：幼年组（1至3岁，n = 14）、成年组（>3至6岁，n = 12）、老年组（>6至9岁，n = 14）和高龄组（>9岁，n = 15）。在进行常规睾丸切除术后，收集睾丸，并主观评估切面白色条纹区域的程度。随后，睾丸组织切片分别用苏木精-伊红和马松三色染色，以评估生殖细胞变性和间质结缔组织的比例。对生殖细胞变性进行半定量严重程度评分，并对生精细胞进行精子指数（SI）和支持细胞指数（SEI）的定量分析。睾丸切面白色条纹的评分随年龄增加，高龄犬高于其他年龄组（p < 0.05）；成年犬和老年犬之间无差异。睾丸间质纤维化的比例在高龄犬中最高（p < 0.05）。观察到年龄与白色条纹区域之间呈正相关（rho = 0.77，p < 0.01），以及年龄与间质纤维化之间呈正相关（rho = 0.63，p < 0.01）。生殖细胞变性的严重程度随年龄逐渐增加，且在各年龄组之间存在差异（p < 0.05）。年龄与曲细精管萎缩呈正相关（rho = 0.93，p < 0.01）。与其他年龄组相比，高龄犬的SI较低（p < 0.05），幼年、成年和老年犬之间的SI无差异。相反，与幼年、成年和老年犬相比，高龄犬的SEI显著更高。年龄与SI之间呈负相关（rho = -0.69），年龄与SEI之间呈正相关（rho = 0.68），差异均具有统计学意义（p < 0.01）。总之，年龄对9岁以上犬睾丸间质纤维化和生殖细胞变性/耗竭的影响较为明显。
