[Antenatal oogenesis in mice and its experimental modification].

Area of Science:

• Reproductive toxicology
• Developmental biology
• Oogenesis

Background:

• Oxytetracycline is a broad-spectrum antibiotic.
• Oocyte development is a sensitive process susceptible to environmental toxins.
• Understanding the impact of antibiotics on female reproductive health is crucial.

Purpose of the Study:

• To investigate the effects of oxytetracycline exposure on mouse oocyte development.
• To determine the impact of timing of administration on toxicological outcomes.

Main Methods:

• Repeated intramuscular injections of oxytetracycline (5 mg/mouse) were administered to mice at specific developmental stages (days 12-13 or 16-17 post-mating).
• Ovarian tissues were analyzed to assess oocyte morphology, mitotic status, and folliculogenesis.
• Pathological and atretic mitoses, oocyte stages (diplotene, dictyotene, pachytene), and follicle initiation were quantified.

Main Results:

• Injections on days 12-13 post-mating increased pathological and atretic mitoses in oogonia and decreased diplotene/early dictyotene stages.
• Injections on days 16-17 post-mating caused significant degeneration of oocytes in pachytene and diplotene stages.
• Folliculogenesis initiation was inhibited by oxytetracycline exposure during these critical periods.

Conclusions:

• Oxytetracycline exposure during early oogenesis disrupts normal cellular processes and germ cell development.
• The timing of antibiotic exposure significantly influences the observed toxicological effects on oocytes.
• These findings highlight potential risks of oxytetracycline to female reproductive capacity.