Quantitative and cytological studies of interstitial (Leydig) cells in the scrotal and retained testes of unilateral cryptorchid West African Dwarf goats

• Hyperplasia of interstitial cells in the scrotal testes of unilateral cryptorchids.
• Atrophy and degeneration of interstitial cells of the retained testes in the cryptorchids.
• Increased elaboration of organelles involved in steroid syntheses.

Cryptorchidism is a common condition in West African Dwarf goats in Eastern Nigeria. The cytology and morphometry of interstitial cells were investigated using light and electron microscopy. Twenty adult male goats were used for the study. Ten of the goats were natural unilateral cryptorchids, while the remaining ten had fully descended testes and served as control. Significant hyperplasia of the interstitial cells were observed in scrotal and retained testes of the unilateral cryptorchid bucks compared to the control (normal) bucks. The number of interstitial cells per cross section of the testes was also significantly higher (P < 0.05) in the contralateral scrotal testes of the unilateral cryptorchids (757.88 ± 29.92) than in the testes of the normal bucks (677.30 ± 25.92). In the contralateral scrotal testes of the unilateral cryptorchids, the interstitial cells had abundant cytoplasmic organelles, particularly mitochondria, Golgi apparatus and smooth endoplasmic reticulum, while the retained testes showed evidence of degeneration characterized by irregular nuclear profile, accumulation of nuclear heterochromatin, abundant lipid droplets, cytoplasmic vacuolations and focal intercellular dilations of interstitial cells. These results suggest that the intra-abdominal testes were significantly degenerated and the impairment was probably from exposure of the testes to higher abdominal temperature. However, the interstitial cells of the contralateral scrotal testes of the unilateral cryptorchid bucks showed normal histology and compensatory hyperplasia.