Effects of Ms4a6d knockout on fertility in female mice

To investigate the effect of membrane-spanning 4-domains subfamily member 6D (MS4A6D) gene knockout on the fertility of female mice.

On the basis of the successful construction of Ms4a6d gene knockout model mice, the homozygous Ms4a6d gene knockout (Ms4a6d^-/-) mice at an age of different weeks were subjected. Mouse genotype was identified with RT-qPCR and agarose gel electrophoresis. HE staining, immunofluorescence assay and ELISA were used to detect serum level of anti-müllerian hormone (AMH), composition of macrophages and follicles at all levels in the ovaries of Ms4a6d^-/- mice, respectively. The fertility changes in pregnant rate and average litter size of female Ms4a6d^-/- mice were observed by fertility experiments.

Compared with the wild-type (Ms4a6d^+/+) female mice at the same age, there were less macrophages in the ovarian tissues of the 2- and 4-week-old Ms4a6d^-/- female mice (P < 0.01), but no significant difference was observed between the 2 types of mice at 8 weeks of age. For the adult Ms4a6d^-/- female mice at an age of 8 weeks, the ovarian coefficient was obviously lower (P < 0.01), and the numbers of primordial, primary, secondary and antral follicles in the ovarian tissues was statistically lower (P < 0.05) when compared with the adult wild-type female mice at the same age. The serum AMH level was notably lower in the Ms4a6d^-/- female mice of all ages than the wild-type ones at corresponding ages (P < 0.05). The average pregnancy rate was 56% and the litter size was 4.1±1.1 in adult Ms4a6d^-/- female mice, which were significantly lower than those of wild-type mice of the same age (89% and 6.3±1.2).

Ms4a6d gene knockout decreases the number of macrophages in the ovarian tissues of adolescent females, interferes with the development of follicles in the ovarian tissues of adolescent females, and leads to a decrease in ovarian reserve in adult females and a decrease in fertility in adult females.