Decreased sperm production in aged testes and functional sperm defects in aged epididymides lead to decreased fertility in male mice.

To analyze mRNA expressions in aged mouse testes and cauda epididymides at genome wide level, we performed mRNA-Seq on these bulk samples at 2, 18, and 24 months. Bulk testes and cauda epididymides in wild-type C57BL/6J mice at 2, 18, and 24 months (five biological replicates for each organ) were placed in TRIzol, homogenized, and obtained the total RNAs.