Testicles - Degenerative Pathology
- DEGENERATIVE CHANGES
Testicular degeneration most common cause of reduced fertility (low sperm count or increased number of abnormal sperm). One or both testes may be involoved depending on whether the cause is local or systemic. Regeneration can occur if the aetiological agent is removed before the spermatogonia are completely destroyed (cf. ovary - no regeneration of ova possible).
Aetiology:
- Infection:localised or systemic infection. Due to toxaemia and pyrexia [see d) below].
- Nutritional deficiency or imbalance:Non-specific - vitamin A (E?) deficiency.
- Chemical:Endogenous, e.g. oestrogen from Sertoli cell tumour. Exogenous, e.g. by alkylating agents or naphthalene compounds.
- Physical:
- hyperthermia - e.g. excess periscrotal fat in obese bulls; congenitally shortened cremaster muscles; pyrexia, cryptorchid.
- increased pressure within the tunica albuginea, e.g. back pressure from blockage of the epididymis, tumour, granuloma.
- ionising radiation.
- Hypoxia - Slowly developing arterial and venous occlusion, e.g. old bulls and dogs.
Gross:Acute - soft flabby testes.Chronic - small firm, calcified.
Histologically:Atrophy due to gradual loss of spermatogonia by apoptosis.
Sertoli cells increase in number with polynuclear giant cells in the seminiferous tubules. Dystrophic calcification of necrotic debris in tubule lumina.
Progressive fibrosis develops around the tubules. May be little inflammation.
Information by kind permission of Professor R W Else