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Post-Doctoral Fellowships
The Effect of BPA on Human Oocyte Maturation – In Vitro Study
The main focus of this research was to investigate the effect of the environmental chemical,
bisphenol A (BPA) on normal human oocyte (egg) development. Potential sources of BPA exposure
include drinking water, air and dust, as well as polycarbonate baby bottles, tableware, white dental
fillings and sealants and the resin lining of cans used in food and beverage products. BPA was
detected in human fluids such as urine, serum, fetal serum, amniotic fluid and follicular fluid, the
fluid that embeds the oocyte.
Immature oocytes (GV) from patients undergoing IVF procedure, which would otherwise be
discarded, were used following patient signed informed consent for donation of their discarded
oocytes for research.
Oocytes from only one cycle of each patient were included in the study. A total of 352 oocytes
were cultured with 0, 20, 200 ng/ml or 20 µg/ml of BPA. Oocytes were then fixed and labeled for
tubulin, actin and chromatin and assessed with confocal microscopy for their meiotic stage. Mature
oocytes (MII) (n=175) were further classified according to their spindle configurations and patterns
of chromosome alignment.
We showed a decrease in the percentage of oocytes that normally developed (progressed to MII) as
the BPA dose increased (p=0.002). As BPA dose increased, there was an increase in the percentage
of oocytes that were degenerated (p=0.01) or that had undergone abnormal spontaneous activation
(p=0.007). Among MII oocytes, as the BPA dose increased, there was a significant decrease in the
incidence of bipolar spindles (p<0.0001) and aligned chromosomes (p=0.02).
Research publications
(1)
Machtinger, R., Combelles, C.M., Missmer, S.A., Correia, K.F., Williams, P., Hauser, R., & Racowsky, C. (2013).
Bisphenol-A and human oocyte maturation in vitro.
Human Reproduction, 28
(10), 2735-2745.
Fellow
Ronit Machtinger
Harvard University, USA
Supervisors
Catherine Racowsky
and Russ Hauser
2010-2012