Canine model of infertility after spinal cord injury: Time course of acutechanges in semen quality and spermatogenesis

Purpose: We established a canine model of subfertility after spinal cord in jury and examined the time course of acute changes in semen quality and spe rmatogenesis after spinal cord injury. Materials and Methods: Seven dogs underwent surgical T7 spinal cord injury. Six dogs were used as controls. Electroejaculation and testicular fine nee dle aspiration were performed at baseline and twice weekly for 3 weeks afte r spinal cord injury. Semen quality change was examined by standard semen a nalysis. Spermatogenesis was assessed by now cytometry of testicular fine n eedle aspiration in all dogs as well as by testicular histology at study co nclusion in 4 controls and 4 spinal cord injured dogs. Results: No significant changes in spinal cord injured dogs were noted befo re 3 weeks after injury. From baseline to 3 weeks after injury certain chan ges were evident in spinal cord injured dogs. Mean antegrade sperm motility decreased from 62.9% to 20.1% (p = 0.008), mean total sperm (antegrade plu s retrograde total sperm) decreased from 423 to 294 X 10(6) which was not s tatistically significant, and the incidence of testicular haploid cells dec reased from 75.6% to 48.3% (p = 0.028). No significant change in any parame ter was present in control dogs. The mean number of mature spermatids per c ross-sectional tubule on final testicular histology was significantly decre ased in spinal cord injured dogs compared with controls (13.6 versus 43.9, p = 0.02). Conclusions: In the canine model tested the dogs readily survived spinal co rd injury, electroejaculation was effective for obtaining ejaculate and fin e needle aspiration allowed serial examination of spermatogenesis. Three we eks after spinal cord injury but not before 3 weeks sperm motility and sper matogenesis were significantly decreased. However, at the same point this d ecrease in spermatogenesis was not yet reflected in the total ejaculated sp erm count.