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1,2-propanediol-induced premature centromere separation in mouse oocytes and aneuploidy in one-cell zygotes
J B Mailhes1, D Young, S N London
1Department of Obstetrics and Gynecology, Louisiana State University Medical Center, Shreveport 71130, USA. jmailh@lsumc.edu
Abstract:
Aneuploidy in germ cells results in reproductive failure and mental and physical disorders in humans. Unfortunately, little is known about the causes and mechanisms of aneuploidy induction. The objective of this study was to test the hypothesis that propylene glycol (1,2-propanediol; PG) induces cytogenetic aberrations in mouse metaphase II (MII) oocytes that predispose zygotes to aneuploidy. Female ICR mice received 7.5 IU eCG and 5.0 IU hCG 48 h later. PG doses of 1300, 2600, and 5200 mg/kg body weight were given 3 h post-hCG; controls received the solvent deionized water. Ovulated oocytes were collected 16 h after administration of PG and processed for cytogenetic analysis. For the one-cell zygote cytogenetic study, females were given PG and paired (1:1) with ICR males for 16 h. Females that mated were given 2 x 10(-3) M colchicine 22 h post-PG, and zygotes were collected 18 h later. PG significantly (p < 0.05) increased both the proportion of MII oocytes with premature centromere separation (PCS) and the proportion of aneuploid one-cell zygotes. These results support the hypothesis that PG-induced PCS in MII oocytes predisposes zygotes to aneuploidy.
Insights
Propylene glycol (PG) exposure in female mice caused premature centromere separation in oocytes, leading to aneuploid zygotes. This finding suggests PG may induce reproductive issues by affecting chromosome segregation.
Area of Science:
- Reproductive biology
- Cytogenetics
- Toxicology
Background:
- Aneuploidy in germ cells is linked to reproductive failure and developmental disorders.
- The mechanisms underlying aneuploidy induction remain largely unknown.
- Investigating environmental factors like propylene glycol (PG) is crucial for understanding reproductive health.
Purpose of the Study:
- To determine if propylene glycol (PG) induces cytogenetic aberrations in mouse oocytes.
- To test the hypothesis that PG-induced aberrations predispose zygotes to aneuploidy.
- To examine the effect of PG on premature centromere separation (PCS) in metaphase II (MII) oocytes.
Main Methods:
- Female ICR mice were administered varying doses of propylene glycol (PG) or a control solvent.
- Ovulated MII oocytes were collected and analyzed for cytogenetic abnormalities.
- One-cell zygotes from PG-treated females were assessed for aneuploidy following mating and colchicine treatment.
Main Results:
- PG significantly increased the proportion of MII oocytes exhibiting premature centromere separation (PCS).
- A significant increase in aneuploid one-cell zygotes was observed in PG-exposed groups.
- A dose-dependent relationship between PG exposure and aneuploidy was suggested.
Conclusions:
- The study supports the hypothesis that propylene glycol (PG) induces premature centromere separation (PCS) in MII oocytes.
- PG-induced PCS in oocytes appears to predispose resulting zygotes to aneuploidy.
- These findings highlight a potential reproductive risk associated with PG exposure.