Effects of Repeated Testicular Biopsies in Adult Warmblood Stallions and Their Diagnostic Potential

Testicular biopsy is still uncommonly used in equine andrological diagnostics although several studies supported that it is a relatively safe procedure. So far, no data exist regarding repeated testicular biopsies in stallions. In the present study, repeated testicular biopsy samples were obtained from four stallions at 4-week intervals alternatingly from both testes over the period of 1 year. The objectives were to assess (1) effects of repeated testicular biopsies by clinical, morphologic, histologic, ultrasonographic, and infrared thermographic examinations and (2) the utility of the biopsy samples for diagnostic purposes, namely hematoxylin-eosin staining, immunohistochemistry, Western blot analysis, and polymerase chain reaction. No significant side effects could be determined on clinical healthiness, testis size, libido, testicular blood flow, testicular histology, and scrotal surface temperature. The biopsy samples provided sufficient tissue for assessing spermatogenesis, detecting and localizing proteins (immunohistochemistry), and for protein/messenger RNA extraction for Western blot analyses and polymerase chain reaction. The authors conclude that taking even repeated testicular biopsies is a practicable and safe technique for equine practice having only minimal side effects. The biopsy specimens are suitable for various diagnostic cell and molecular biology applications for identifying testicular causes of male equine infertility. Prospectively, also therapeutic applications might be possible to extend the prospects of already established assisted reproductive techniques (e.g., testicular sperm extraction followed by intracytoplasmic sperm injection) in stallions suffering from obstructive azoospermia or oligospermia. Repeated testicular biopsies might also provide benefits for scientific work, for example, to monitor effects of pharmaceuticals or seasonal variations on testis function and spermatogenesis in the same animal.