Telomeres are non-coding, repetitive DNA sequences (TTAGGG repeats) that play an important role in maintaining genome integrity. Unlike in somatic cells, telomere length in spermatozoa increases with male age and is considered as a molecular marker of sperm quality. The aetiology of failed fertilization following intracytoplasmic sperm injection (ICSI) is multifactorial; perhaps one of the reasons for this failure in these individuals is shortened sperm telomere length. This study therefore aimed to assess sperm telomere length in addition to DNA damage, lipid peroxidation and protamine deficiency in infertile men with previously failed/low fertilization post-ICSI.
Semen samples were obtained from infertile men with previous failed/low fertilization rates (n = 10). Chromatin integrity (chromomycin A3 staining and TUNEL assay), lipid peroxidation (BODIPY probe) and telomere length (real-time PCR) for semen samples from these men were compared with samples obtained from fertile individuals (n = 10).
The results showed significantly higher mean values for sperm DNA damage, lipid peroxidation and reduced telomere length in spermatozoa of infertile men with previous failed/low fertilization compared with fertile individuals (P < 0.05).
Failed/low fertilization rates could be related to oxidative stress resulting in short telomere length, and also increased sperm chromatin damage and lipid peroxidation. From literature sources, shortened telomere length may lead to detachment of chromosomes from the nuclear membrane, the consequences of which are defects in the process of spermatogenesis, pronuclei formation, and delayed or arrested cell cycle post-ICSI.
Reproductive biomedicine online. 2018 Dec 23 [Epub ahead of print]
Zahra Darmishonnejad, Marziyeh Tavalaee, Tayebeh Izadi, Somayeh Tanhaei, Mohammad Hossein Nasr-Esfahani
ACECR Institute of Higher Education (Isfahan Branch), Isfahan, Iran; Department of Reproductive Biotechnology, Reproductive Biomedicine Research Centre, Royan Institute for Biotechnology, ACECR, Isfahan, Iran., ACECR Institute of Higher Education (Isfahan Branch), Isfahan, Iran., Department of Cellular Biotechnology, Cell Science Research Centre, Royan Institute for Biotechnology, ACECR, Isfahan, Iran., Department of Reproductive Biotechnology, Reproductive Biomedicine Research Centre, Royan Institute for Biotechnology, ACECR, Isfahan, Iran; Isfahan Fertility and Infertility Centre, Isfahan, Iran. Electronic address: .