Expression of heat shock protein 70 in normal and cryptorchid human excurrent duct

The Hsp70 heat-shock proteins are molecular chaperones that assist other proteins in their folding, transport and assembly into complexes. Most of these proteins are either constitutively expressed or induced by heat shock and other stresses. Heat shock proteins are required for spermatogenesis, and also protect cells from environmental hazards such as heat, radiation, and chemicals. The abdominal position of the cryptorchid testis provokes a temperature elevation which is detrimental to spermatogenesis and causes infertility. The consequences of such a stress on Hsp70 expression were evaluated in normal and cryptorchid epididymides and vas deferens. Hsp70-1 transcript from reproductive organs of normal and cryptorchid men was analysed by real-time quantitative RT-PCR, meanwhile Hsp70 protein was characterized by western blot and immunohistochemical staining analysis. Hsp70-1 mRNA and protein showed equal expression in all segments of normal epididymis and ductus deferens. Hsp70 was specific to basal cells in the epididymal epithelium. For cryptorchid patients, Hsp70-1 mRNA expression in caput epididymidis was unchanged compared with controls. However, in corpus and cauda epididymides as well as in vas deferens, the expression level of Hsp70-1 transcript was higher for the cryptorchid tissues. Changes in mRNA frequency were specifically correlated with the age of the patients. By opposition to the mRNA, western blot analysis revealed that Hsp70 protein levels were not affected by the inguinal location of the epididymis. The data show that Hsp70-1 transcript and protein were constitutively expressed in human excurrent duct and that an inguinal location can stimulate the expression of Hsp70-1 mRNA along the human epididymis and ductus deferens.