一般精蟲細胞膜為glycocalyx表面帶負電
約有94%精蟲表面帶負電
可使用微電泳篩顯帶負電之精蟲再進行傳統離心分離精蟲
傳統離心分離精蟲會改變精蟲表面之帶電性
表面帶負電之精蟲進行傳統離心分離後DNA受損率較低

J Assist Reprod Genet. 2016 Mar 23. [Epub ahead of print]

Optimization of microelectrophoresis to select highly negatively charged sperm.

Simon L1, Murphy K1, Aston KI1, Emery BR1, Hotaling JM1, Carrell DT2,3,4.

Author information

Abstract

PURPOSE:

The sperm membrane undergoes extensive surface remodeling as it matures in the epididymis. During this process, the sperm is encapsulated in an extensive glycocalyx layer, which provides the membrane with its characteristic negative electrostatic charge. In this study, we develop a method of microelectrophoresis and standardize the protocol to isolate sperm with high negative membrane charge.

METHODS:

Under an electric field, the percentage of positively charged sperm (PCS), negatively charged sperm (NCS), and neutrally charged sperm was determined for each ejaculate prior to and following density gradient centrifugation (DGC), and evaluated for sperm DNA damage, and histone retention. Subsequently, PCS, NCS, and neutrally charged sperm were selected using an ICSI needle and directly analyzed for DNA damage.

RESULTS:

When raw semen was analyzed using microelectrophoresis, 94 % were NCS. In contrast, DGC completely or partially stripped the negative membrane charge from sperm resulting PCS and neutrally charged sperm, while the charged sperm populations are increased with an increase in electrophoretic current. Following DGC, high sperm DNA damage and abnormal histone retention were inversely correlated with percentage NCS and directly correlated with percentage PCS. NCS exhibited significantly lower DNA damage when compared with control (P < 0.05) and PCS (P < 0.05). When the charged sperm population was corrected for neutrally charged sperm, sperm DNA damage was strongly associated with NCS at a lower electrophoretic current.

CONCLUSION:

The results suggest that selection of NCS at lower current may be an important biomarker to select healthy sperm for assisted reproductive treatment.