Chronic Immune-Mediated Orchitis Is the Major Cause of Acquired Non-obstructive Azoospermia in Dogs.

Azoospermia, the lack of spermatozoa in the ejaculate, is the most common finding in infertile but otherwise healthy male dogs and represents an increasing reproductive health issue in men, too. The diagnosis can be further classified as non-obstructive azoospermia and obstructive azoospermia due to an obstruction of the deferent ducts. Although non-obstructive azoospermia comprises more than half of azoospermic cases in men and is a common cause of infertility in the male dog, knowledge of the underlying etiology and pathophysiology is still strongly limited, and much uncertainty exists about the true incidence and possible treatment options. Therefore, this study aims to investigate and characterize infertile canine patients in detail by combining results of andrological examinations (clinical parameters, semen analysis, bacterial examination of semen, and Brucella canis serology), endocrine analysis (luteinizing hormone, testosterone, estradiol-17ß, and thyroid function), analysis of the alkaline phosphatase in seminal plasma, and histological assessment of testicular biopsies of 10 azoospermic dogs. Our results not only verify non-obstructive etiology for 9/10 cases of canine azoospermia but also further identified significant histopathological changes of the testicular tissue with severely disrupted spermatogenesis, including fibrotic remodeling, vacuolization, Sertoli-cell-only syndrome, tubular shadows, and an increase of the interstitial and vascular area. In addition, three dogs showed local and six dogs generalized immune-cell infiltration, indicating chronic immune-mediated orchitis. Only in one case (no. 1) that no immune cells were found, and obstructive azoospermia was suspected due to low alkaline phosphatase activity. Furthermore, the detection of anti-thyroideal antibodies in two dogs indicates an autoimmune thyroid disease and a correlation between the occurrence of thyroidal disorders and azoospermia. Our results confirm previous findings and contribute additional evidence suggesting that chronic immune-mediated orchitis is the major cause of infertility in dogs. Further studies should focus on uncovering underlying inflammatory processes behind spermatogenic failure in these cases and identify possible treatment options to (re-)initialize spermatogenesis.

Freezing and storage effects on enzyme, electrolyte, and mineral compositions in canine prostatic fluid.

BACKGROUND: There is a paucity of information about the storage stability of seminal plasma components in literature. OBJECTIVES: This study investigates the potential effects of storage at -18.0°C on the enzyme activities and concentrations of selected electrolytes and minerals in canine prostatic fluid. METHODS: Semen was obtained in fractions from ten male dogs, and the third ejaculate fraction was analyzed immediately after sampling and after storage at -18.0°C for 7 days. The following analytes were assessed: gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), sodium, potassium, total calcium, inorganic phosphate, magnesium, zinc, and copper. RESULTS: Whereas electrolyte and mineral concentrations were not affected by freezing and 7 days of storage, effects on the enzyme activities were variable. ALP, AST, and LDH activities were significantly decreased (P < .05) in the post-thaw samples compared with the freshly prepared samples. CONCLUSIONS: Because freezing and storage of seminal plasma at -18°C had an impact on the activity of some enzymes, analyses should be performed in fresh, not frozen samples.

Concentrations of minerals in the canine prostatic fluid.

Current knowledge about the composition of the prostate fluid in healthy male dogs is limited and restricted to small case numbers. Furthermore, published data often vary significantly regarding sample processing and analytical methods. Therefore, we aimed to provide data on the composition of electrolytes and minerals in the canine prostatic fluid in a larger population (n = 30 dogs/samples) and to compare these results with the existing literature. Concentrations of sodium, potassium and copper analysed in our population were most consistent with those in the literature. Different to this, concentrations of total calcium, magnesium, zinc and inorganic phosphate varied. Whereas magnesium, zinc and inorganic phosphate seemed to depend on the analysis method, total calcium concentrations differed if centrifugation was performed or not. Our results clearly indicate a need for standardization of methods for analysis of seminal plasma components.