Cigarette smoke reduces transport of hamster eggs

Eggs of female hamsters are significantly less likely to be transported by the oviduct when the eggs or the oviduct have been exposed to cigarette smoke, and this could result in disruption of fertilization and pregnancy, according to reproductive scientists at the University of California, Riverside.

In a paper to be published in Biology of Reproduction, Christine Gieseke and Prue Talbot report that various types of cigarette smoke cause freshly ovulated hamster eggs, enveloped in a layer of cumulus cells, to stick to the upper part (infundibulum) of the oviduct so that cilia are unable to transport them to the point where fertilization occurs.

Gieseke and Talbot found that both the cumulus-coated eggs and the oviducts of hamsters are affected by cigarette smoke, although the oviduct experiences more adverse effects, possibly because the cilia are also impaired by the smoke.

When the infundibular region of the hamster oviduct was exposed to six types of cigarette smoke, eggs were 50% to 90% more likely to stick to the infundibulum than was the case in control animals, and 40% to 60% fewer eggs were transported through the oviduct.

When cumulus-coated hamster eggs were exposed to cigarette smoke, adhesion to the infundibulum increased by 40% to 55% and egg transportation rates dropped by 20% to 35%.

In an accompanying comment on this paper, Biology of Reproduction co-editor Mary Ann Handel notes that the work of the UC Riverside researchers on egg transport will "open the door to future molecular analysis of this process as well as provide one more cautionary note about significant health effects of smoking."

Biology of Reproduction, published by the Society for the Study of Reproduction, is the top-rated peer-reviewed journal in the field of reproductive biology.

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