A new approach to evaluate aging effects on human oocytes: Fourier transform infrared imaging spectroscopy study

Objective: To characterize from a vibrational point of view the alterations caused by aging on human oocytes.

Design: Reproductive biology.

Setting: Private assisted reproductive technology clinic, synchrotron beam line, and university infrared laboratory.

Patient(s): Twenty women of different ages (30 ± 2 and 39 ± 2 years) selected on the basis of detailed inclusion criteria and submitted to controlled ovarian stimulation according to a specific protocol.

Intervention(s): Collection of 68 supernumerary oocytes that were not used during the IVF cycle from the above cited consenting patients.

Main outcome measure(s): Focal Plane Array Fourier transform infrared (FTIR) analysis of human oocytes.

Result(s): Specific spectral differences were highlighted in the two experimental groups of oocytes. In particular, in oocytes of 39-year-old women, the occurrence of peroxidative processes and a decrease in the amount of carbohydrates were observed, together with alterations in the phospholipid membrane, proteic pattern, and nucleic acids content.

Conclusion(s): For the first time, FTIR spectroscopy was applied to human oocytes, leading to strong evidence of damage from aging in the gametes of mature women, which could be related to a decline in reproductive function. All the information obtained may be considered useful to improve the scientific knowledge on human reproduction and to exploit new strategies for detecting oocyte aging.