SAN FRANCISCO (September 23, 2008). The OosightTM is a new tool for the IVF Laboratory. Laurel Fertility Care has become possibly the first, and only, in vitro fertilization (IVF) program in the San Francisco Bay Area to incorporate the OosightTM into their routine IVF laboratory. The OosightTM, also known as a polscope, is installed on a high resolution microscope and allows the observer to identify the presence of the meiotic spindle within an egg. The spindle is associated with the chromosomes in the nucleus of the egg.
“Using the OosightTM, we can determine where the nucleus of the egg is when we do Intracytoplasmic Sperm Injection (ICSI).” The ICSI procedure is used following the removal of eggs from the ovaries, where a single sperm is injected into a single egg.
“This enables us to make sure we aren’t disrupting the nucleus during injection of sperm into the egg,” said Marlane Angle, PhD, the laboratory director at Laurel Fertility Care in San Francisco.
Previously during ICSI, the presence of the nucleus could only be assumed to be located near the polar body, a small structure that is extruded from the surface of the egg as it matures. The polar body contains genetic material, the DNA, that the egg is getting rid of as it undergoes meiosis. In the normal, mature egg, the remaining DNA should lie within a short distance of the polar body. If this region is avoided during ICSI the embryologist can only hope to be able to avoid injecting the sperm directly into the nuclear region of the egg because the nucleus cannot be seen using normal light microscopy.
However several new studies have shown that the nucleus is not always where it should be. Therefore, during injection of sperm into an egg at the time of ICSI, the process may disrupt the interior of the egg enough to disrupt the nucleus. This can lead to problems with division of the embryo. The OosightTM uses polarized light that causes the spindle apparatus to show up as a bright spot within the egg. The embryologist is then able to avoid this region during ICSI, providing optimal conditions for fertilization.
An additional benefit of the OosightTM that Dr. Angle is currently investigating is whether the absence of a visible spindle within the egg may predict subsequent problems with fertilization, or even of division after fertilization. In turn this may allow the embryologist to gain more information that will help them select the best embryos for transfer back into the uterus of the patient, thereby improving pregnancy rates.
“This is pretty new technology. However the nice thing about the OosightTM is that its use is observational only. It is not invasive. Therefore, we can be confident that using the Oosight will not cause any damage or harm to the egg or the embryo, only benefit. We are very excited to be able to have this cutting-edge technology here at Laurel Fertility Care,” Dr. Angle said.
The OosightTM is manufactured by Cambridge Research & Instrumentation, Inc (CRi), a Boston-based biomedical imaging company.