Effect of 1,2-propanediol and dimethylsulphoxide on the meiotic spindle of the mouse oocyte

At ovulation, the mouse oocyte is arrested at metaphase of thesecond meiotic division. Since microtubules are thermo-and chemosensitivestructures, the effects of 1.5 M dlmethylsulphoxide and 1.5M 1,2-propanediol were studied at room temperature on the morphologyof the meiotic spindle. Oocytes incubated at 37°C or atroom temperature served to estimate the effect of temperaturein the experiment. The meiotic spindle was visualized by immunogold-silverstaining of microtubules. In the control group at 37°C,88% of oocytes had normal spindles. After incubation at roomtemperature for the same time, 89% of oocytes showed abnormalspindles. In the oocytes exposed to dimethyl sulphoxide or 1,2-propanediolat room temperature a protective effect on spindle morphologycould be recognized. Subsequent incubation at 37°C resultedin partial restoration of the observed abnormalities after coolingto room temperature and after exposure to dhnethytsulphoxide.incubation at 37°C after exposure to 1,2-propanediol atroom temperature induced spindle absence in the majority ofoocytes. Although this latter condition allowed fertilizationwithout increased incidence of ploidy abnormalities, a rolefor 1 as an activating agent is hypothesized.