Changes in aortic endothelium ultrastructure in male rats following castration, replacement with testosterone and administration of 5alpha-reductase inhibitor.

Aim: To investigate the relationship between low androgen level and ultrastructure of vascular endothelium.

Methods: Forty-eight male Sprague-Dawley rats were randomly divided into four groups: group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone (T) undecanoate; and group D, intact rats treated with 5alpha-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T (FT) and dihydrotestosterone (DHT) were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score (VESS) was computed.

Results: Serum T and FT concentrations of rats in group B were significantly lower than those of the other three groups (P < 0.01); DHT concentrations of group D rats were significantly decreased (P < 0.01) when compared with those of groups A and C. Rats in groups B and D rats (with low androgen levels) had obvious damage to their endothelial surfaces, which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS.

Conclusion: These results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.