During their transit through the epididymis, spermatozoa undergo many biochemical modifications necessary to acquire flagellar motility and fertilizing ability. These modifications, collectively called sperm maturation, are well orchestrated along the epididymis and depend on highly regionalized gene expression patterns. Based on clinical observations, the role of the epididymis in human sperm maturation has been questioned. To further understand the function of the excurrent duct in humans, we analysed gene expression of three donors on 'Affymetrix human GeneChip U133 plus 2' representing 47,000 transcriptional variants. More than 50% of transcripts were detected in each epididymal region. The analysis of hierarchical clustering performed from 2274 modulated qualifers between the three regions revealed that 1184, 713 and 269 were highly expressed in the caput, corpus and cauda region, respectively, in a very specific manner. The expressed qualifers were grouped according their similarity by Gene Ontology to give an overview of the functional features of the encoded proteins and to elucidate their potential roles in the epididymis. Northern blot analysis of eight gene transcripts predicted by microarray data to be highly expressed in the human epididymis was performed. All the transcript expression patterns confirmed the microarrays results. The data generated in this study demonstrate a region-specific gene expression pattern along the human epididymis that seems to coincide with the morphologically distinctive features of the excurrent duct.

Worldwide, almost 100 million men rely on vasectomy for male contraceptive purposes. Due to changes in their personal lives, an increasing number of these men request surgical vasectomy reversal. Unfortunately, a significant proportion of these men remain infertile, despite the reestablishment of patent ducts, possibly due to epididymal damage caused by vasectomy. In animal models, vasectomy affects different epididymal physiological and biochemical parameters. However, the consequences of vasectomy on epididymal function are poorly understood. Furthermore, results obtained with animal models cannot be extrapolated to humans to understand the consequences of vasectomy on epididymal function. Gene expression along the epididymis is highly regulated. We previously showed that the human epididymal expression pattern of two genes is altered after vasectomy. To complete the list of epididymal genes affected by vasectomy, we analyzed the epididymal gene expression pattern of three vasectomized donors using the Affymetrix human GeneChip U133 Plus 2. These results were compared with the gene expression pattern of three "normal" donors. The data generated allowed the identification of many human epididymal genes for which expression is modified after vasectomy. Quantitative (Qt)-PCR and Western blot analysis of six selected genes known to be expressed in specific epididymal segments were performed. The Qt-PCR results confirmed the selected transcripts expression pattern deduced from microarray data. However, Western blot analysis revealed some differences in protein distribution along the epididymis when compared with the encoding transcripts expression pattern. These results contribute to an understanding of the reasons why fertility is not recovered in vasovasostomized men, even though spermogram values suggest surgical success of vasectomy reversal.