Impairment of blood-testis barrier integrity can be observed during inflammation, infection, trauma and experimental autoimmune orchitis, which is inducible in rodents. In the present study, an initially fertile two-year-old Beagle dog was presented with a decline in total sperm number resulting in azoospermia within five months, verified by twice-monthly semen analyses. The dog was clinically healthy with bilateral small testes and showed normal thyroid function. Bacterial cultures of semen were negative and serum biochemical analyses showed no abnormal findings. To determine causes of azoospermia, the dog was castrated. Histological examinations of hematoxylin-eosin stained testicular sections revealed impaired spermatogenesis, seminiferous tubules with spermatogenic arrest or Sertoli-cell-only syndrome as well as focal interstitial and even intratubular lymphocytic infiltrations. Germ cell sloughing, apoptosis and giant cells were also observed in some tubules. Subsequent immunostainings of smooth-muscle-actin, claudin3, claudin11 and connexin43 demonstrated, for the first time, a mechanical and functional disruption of the tubular wall and alterations of blood-testis barrier proteins in these tubules. Presence of claudin3 and claudin11 in canine testis was confirmed using RT-PCR and sequencing and/ or Western-blot analyses. All findings suggested a possible spontaneous autoimmune orchitis to be the underlying cause for the observed azoospermia.

中文翻译：

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不育的比格犬的精子发生受损，肾小管壁破坏，血液-睾丸屏障成分改变和肾小管内淋巴细胞改变-这是自身免疫性睾丸炎的假定病例。

在炎症，感染，创伤和实验性自身免疫性睾丸炎期间可以观察到血液-睾丸屏障完整性的损害，这在啮齿动物中是可诱导的。在本研究中，出现了最初可育的两岁小猎犬，其精子总数下降，导致五个月内无精子症，并通过每月两次精液分析得到证实。该犬临床健康，双侧小睾丸，甲状腺功能正常。精液细菌培养阴性，血清生化分析未见异常发现。为了确定无精症的原因，将狗去势。苏木精-伊红染色的睾丸切片的组织学检查显示，精子发生受损，伴生精停止或仅支持细胞的精小管以及局灶性间质甚至肾小管内淋巴细胞浸润。在某些肾小管中还观察到生殖细胞脱落，凋亡和巨细胞。随后的平滑肌肌动蛋白，claudin3，claudin11和connexin43的免疫染色首次证明了这些小管中管壁的机械和功能破坏以及血液-睾丸屏障蛋白的改变。使用RT-PCR和测序和/或Western印迹分析确认犬睾丸中claudin3和claudin11的存在。所有发现均提示自发性自身免疫性睾丸炎可能是无精症的根本原因。随后的平滑肌肌动蛋白，claudin3，claudin11和connexin43的免疫染色首次证明了这些小管中管壁的机械和功能破坏以及血液-睾丸屏障蛋白的改变。使用RT-PCR和测序和/或Western印迹分析确认犬睾丸中claudin3和claudin11的存在。所有发现表明，可能的自发性自身免疫性睾丸炎是观察到的无精症的根本原因。随后的平滑肌肌动蛋白，claudin3，claudin11和connexin43的免疫染色首次证明了这些小管中管壁的机械和功能破坏以及血液-睾丸屏障蛋白的改变。使用RT-PCR和测序和/或Western印迹分析确认犬睾丸中claudin3和claudin11的存在。所有发现表明，可能的自发性自身免疫性睾丸炎是观察到的无精症的根本原因。