Effects of caloric restriction on gene expression along the epididymis of the Brown Norway rat during aging.

Aging in the Brown Norway (BN) rat, is associated with changes in the male reproductive tract. In the epididymis, the site of sperm maturation and storage, aging has profound effects on the histology, biochemistry and gene expression of the tissue. Caloric restriction consistently slows aging and maintains health in aging animals. The goal of this study was to assess the effects of caloric restriction on aging-related changes in gene expression in the BN rat epididymis using cDNA microarrays. Caloric restriction attenuated or reversed age-related gene expression changes throughout the epididymis. In the distal regions of the tissue (corpus and cauda epididymidis), greater than 80% of the gene expression decreases were attenuated by caloric restriction. In the most proximal region of the tissue (initial segment), caloric restriction affected the expression of genes associated with lipid and carbohydrate metabolism. In all regions of the epididymal epithelium, caloric restriction had a dramatic effect on the age-related decreased expression of genes associated with protein synthesis and mitochondrial function. These results indicate that caloric restriction lessens age-related mitochondrial dysfunction and improves protein synthetic capability throughout the epididymis.