Sperm Preparation for IVF and ICSI doc

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Sperm Preparation for IVF and ICSI

Nancy L. Bossert and Christopher J. De Jonge

Reproductive Medicine Center, University of Minnesota,

Minneapolis, Minnesota, U.S.A.

INTRODUCTION

Human spermatozoa at ejaculation are incapable of in vivo fertilization and

must undergo maturational change during which they acquire the ability to

fertilize oocytes. This process, known as capacitation, was described more

than 50 year ago by both Austin (1) and Chang (2). Capacitation is preven￾ted in ejaculated spermatozoa by at least one factor in seminal plasma (3).

Additionally, prolonged exposure to seminal plasma can inhibit the ability

of spermatozoa to undergo the acrosome reaction in vitro (4) and diminish

their capacity to fertilize (5). In the female genital tract, motile spermatozoa

separate themselves from seminal plasma, immotile spermatozoa, and debris

by actively migrating through the cervical mucus. This active migration

selects progressively motile spermatozoa and allows them to undergo

capacitation. Due to the inhibitory effects of seminal plasma on sperm func￾tion, it is critical that spermatozoa used for clinical procedures such as

in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) be

separated from the seminal plasma as quickly as possible after ejaculation

and liquefaction.

Although IVF started as a treatment for tubal infertility, the increas￾ing number of men with poor semen quality led to the development of a

variety of sperm preparation techniques. These techniques generally fall

into four categories: (i) simple dilution and washing, (ii) sperm migration,

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