Histology and mRNA expression of unilateral testicular atrophy in three immunocastrated boars: a case report

BACKGROUND: This case study reports testicular asymmetry in entire male (EM) and immunocastrated pigs (IC), specifically focusing on histomorphometric and transcriptomic characteristics of testicular and epididymal tissue in three IC with pronounced unilateral testicular atrophy. CASE PRESENTATIONS: During post-mortem assessment of genital tract, three IC were identified with marked testicular asymmetry. Testes and cauda epididymides were collected from these animals for histomorphometric analysis and quantitative polymerase chain reaction (qPCR). In addition, percentage of testicular asymmetry was calculated in a broader cohort of EM and IC pigs to assess prevalence and degree of asymmetry. CONCLUSION: The observed cases of severe unilateral atrophy did not appear to be systematically related to immunocastration, based on available data. In atrophic testes, there were distinct histological differences in testes and cauda epididymides, along with molecular changes, including downregulation of gonadotropin-releasing hormone receptor II (GnRHRII), estrogen receptor 1 (ESR1) and betaine homocysteine S-methyltransferase (BHMT), but no marked differences in plasma testosterone concentrations nor immunocastration efficacy. Although based on a limited number of cases, these findings provided the first combined histological and molecular characterization of unilateral testicular atrophy in immunocastrated boars.