Seul Ki Kim1, Byung Chul Jee2, Seok Hyun Kim3. 1. Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, South Korea; Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea. 2. Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, South Korea; Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea. Electronic address: blasto@snubh.org. 3. Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea; Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul, South Korea.
Abstract
OBJECTIVE: To assess global methylation and acetylation level before and after swim-up in ejaculated human sperm. DESIGN: Prospective experimental study. SETTING: University-based hospital. PATIENT(S): Semen samples were obtained from 50 healthy volunteers (single sample per person) between December 2012 and May 2014. INTERVENTION(S): The semen samples were processed by the swim-up method. MAIN OUTCOME MEASURE(S): Sperm motility, strict morphology, DNA fragmentation index (DFI) by TUNEL, abnormal chromatin structure by toluidine blue staining, immunostaining of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as an oxidative stress marker, immunostaining of 5-methyl-cytosine (5-mC) as a measurement of methylation level and immunostaining of six acetylation markers (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac) before and after swim-up. RESULT(S): After swim-up, motility and the percentage of normal form was significantly elevated. In the swim-up fraction, DFI and the percentage of abnormal chromatin structure were significantly lower and 8-OHdG levels were significantly higher. The 5-mC levels were significantly lower in the swim-up fraction, whereas no changes were observed in the positivity of six acetylation markers. Elevated percentage of normal form and decreased DFI and 5-mC levels were observed only in nonsmokers; 8-OHdG level was significantly higher in the swim-up fraction only from smokers. After swim-up, 5-mC levels were positively correlated with DFI. CONCLUSION(S): This is the first study demonstrating decreased methylation and unchanged acetylation patterns in human sperm after swim-up preparation.
OBJECTIVE: To assess global methylation and acetylation level before and after swim-up in ejaculated human sperm. DESIGN: Prospective experimental study. SETTING: University-based hospital. PATIENT(S): Semen samples were obtained from 50 healthy volunteers (single sample per person) between December 2012 and May 2014. INTERVENTION(S): The semen samples were processed by the swim-up method. MAIN OUTCOME MEASURE(S): Sperm motility, strict morphology, DNA fragmentation index (DFI) by TUNEL, abnormal chromatin structure by toluidine blue staining, immunostaining of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as an oxidative stress marker, immunostaining of 5-methyl-cytosine (5-mC) as a measurement of methylation level and immunostaining of six acetylation markers (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac) before and after swim-up. RESULT(S): After swim-up, motility and the percentage of normal form was significantly elevated. In the swim-up fraction, DFI and the percentage of abnormal chromatin structure were significantly lower and 8-OHdG levels were significantly higher. The 5-mC levels were significantly lower in the swim-up fraction, whereas no changes were observed in the positivity of six acetylation markers. Elevated percentage of normal form and decreased DFI and 5-mC levels were observed only in nonsmokers; 8-OHdG level was significantly higher in the swim-up fraction only from smokers. After swim-up, 5-mC levels were positively correlated with DFI. CONCLUSION(S): This is the first study demonstrating decreased methylation and unchanged acetylation patterns in human sperm after swim-up preparation.