Use of a laser to detect viable but immotile spermatozoa

Abstract

A prerequisite for the success of intracytoplasmic sperm injection (ICSI) is the use of viable sperm that will support oocyte activation and embryo development. Usually, spermatozoa are selected according to motility, which is a clear indication for viability. However, in cases with complete asthenozoospermia, it is impossible to select viable sperm by morphological means. Here we report for the first time on the use of a laser to discriminate between viable and dead immotile spermatozoa. The application of a single laser shot to the far end of the sperm tail causes a curling of the sperm tail only in viable sperm, similar to the reaction observed in the hypo-osmotic swelling test. Using this method for sperm selection prior to ICSI we achieved high fertilization and cleavage rates in cases with immotile sperm in fresh testicular biopsy material as well in cases with ejaculated immotile sperm. It is concluded that laser sperm interaction allows for the identification of viable but immotile spermatozoa.

Optimizing TESE‐ICSI by laser‐assisted selection of immotile spermatozoa and polarization microscopy for selection of oocytes

“…As control experiment for laser function we first analysed if the testing described by Aktan et al (2004) works in our setting. Therefore, we used motile ejaculated spermatozoa from a normozoospermic patient, immobilized them by agitation with an ICSI needle and collected them in a PVP drop.…”

“…Therefore, we used motile ejaculated spermatozoa from a normozoospermic patient, immobilized them by agitation with an ICSI needle and collected them in a PVP drop. By exposing these spermatozoa to a laser shot we could detect a curling or bending of the tail (equal to Aktan et al, 2004). To test the laser method on immotile, but viable spermatozoa, we analysed two ejaculates from asthenozoospermic patients with their samples exhibiting 0% motility and 1% eosin negative and therefore vital sperm on the corresponding day.…”

“…All collected immotile spermatozoa were exposed to a single shot (6-7 ms) of a 1.48 lm wavelength diode laser according to the method of Aktan et al (2004). If a curling of the tail was observed, this spermatozoon was allocated to the vital, otherwise to the non-vital group.…”

“…ICSI with these spermatozoa resulted in equal fertilisaton (FR) and pregnancy rates (PR) in comparison to motile testicular spermatozoa. Aktan et al (2004) developed an alternative technique using a single laser shot directed to the tip of the spermatozoon′s flagellum. Viable spermatozoa were distinguished from non-viable ones as the flagellum formed a coil at the site of impact.…”

Healthy twin live-birth after ionophore treatment in a case of theophylline-resistant Kartagener syndrome

“…Thus, Gerber and co-workers [13] used a 1.48 μm diode laser in order to artificially create a HOS-positive like tail curling as recommended by others [25].…”