Normalization of reproductive function in germfree mice following bacterial contamination

Area of Science:

• Microbiology
• Reproductive Biology
• Germ-free Research

Background:

• Reproductive capacity in germ-free mice is typically inferior to conventionally raised mice.
• Standard improvements in diet and rearing conditions do not fully restore reproductive function in germ-free models.

Purpose of the Study:

• To investigate the impact of bacterial association on the reproductive capacity of germ-free mice.
• To identify specific bacterial species that can restore reproductive function in germ-free mice.

Main Methods:

• Accidental bacterial contamination of germ-free mice and subsequent observation of reproductive parameters.
• Oral administration of fecal suspensions from contaminated mice to germ-free mice.
• Di-association and mono-association experiments with identified bacterial species (B. distasonis, C. perfringens, B. subtilis).
• Evaluation of estrous cycle normalization, copulation rates, implantation rates, and sperm motility.

Main Results:

• Accidental bacterial contamination normalized estrous cycles and increased copulation and implantation rates in female germ-free mice.
• Oral administration of fecal suspensions mimicked these positive reproductive effects.
• Di-association with B. distasonis and C. perfringens restored estrous cycles and improved copulation and implantation rates.
• B. subtilis mono-association did not significantly improve reproductive parameters compared to germ-free controls.
• Bacterial contamination significantly increased sperm motility in male germ-free mice.

Conclusions:

• Bacteroides distasonis and Clostridium perfringens are key bacterial species capable of restoring reproductive function in germ-free mice.
• These bacteria normalize estrous cycles and enhance copulation and implantation rates, comparable to conventional mice.
• The gut microbiome plays a crucial role in mammalian reproductive health.