Studies of cryptorchidism in experimental animal models

Undescended testes are the most common inborn anomaly in boys but our understanding of the causes is still sparse. Experimental models of cryptorchidism in various species of animals have been used by many investigators in order to gain a better understanding of the aetiology, pathophysiology and potential treatment of the disorder. This review presents what has been gained so far by studies using experimental animal models of cryptorchidism. Conclusions: Early orchidopexy in experimentally cryptorchid animals of different species prevents, at least partially, against testicular damage and infertility. This supports an early intervention strategy in the management of cryptorchidism in humans although animal data on the correct timing of such treatment cannot be directly translated into human clinical practice due to the species differences in pre and postnatal testis maturation. Treatment with pharmacological doses of hCG has poor efficacy in experimental animals and may cause adverse effects. Thus, clinically relevant doses of hCG causes acute inflammation-like changes in rodent testes and there are also indications that it may induce morphologically detectable permanent testicular damage.