Sperm Preparation Techniques for Artificial Insemination - Comparison of Sperm Washing, Swim Up, and Density Gradient Centrifugation Methods

The Artificial Insemination (AI) is the first option treatment for infertile couples with cervical factor subfertility, mild-moderate male subfertility and unexplained infertility. With the exception of cases in which the use of in vitro fertilization (IVF or ICSI) is strictly due as a consequence of a severe male or female factor, the artificial insemination must be part of a gradual approach to the techniques of artificial insemination. This is particularly the case since the AI is a valid low-cost method, minimally invasive and easily acceptable for the female’s hormone treatment (Aribarg & Sukcharoen, 1995). The AI, as other assisted reproductive techniques, needs a selection of the ejaculated spermatozoa before the performance of the treatment. In fact, some components of the seminal fluid may become an obstacle to the fertilization when the in vitro fertilization or the intrauterine insemination are performed (Bjorndahl et al., 2005). Spermatozoa and leukocytes produce many oxygen radicals that alter the possibility of the sperm-oocyte fusion after repeated centrifugations. So, the selection of the sperms from the other components with methods like the swim up technique or the gradient density centrifugation must be preferred (Aitken & Clarkson, 1988). Some different techniques are used to prepare the spermatozoa for the AI, but the choice strongly depend on the quality of the semen, that is on the concentration, motility and morphology, in order to obtain the higher number of good spermatozoa, even from the poorest semens. The principle techniques of sperm preparation consist of migration, density gradient centrifugation and filtration techniques. While for the migration the method is based on movement of the spermatozoa, for density gradient centrifugation and filtration techniques the method is based on a combination of the motility and the retention at phase borders and adherence to filtration matrices, respectively (Henkel & Schill, 2003). The main techniques used for the AI are the sperm washing, the swim-up technique, and the density gradient centrifugation and they will be described as follow. The aim of the present chapter is to shed light on the key principles and the best method for sperm selection in order to obtain higher pregnancy rate.