Background: Mitoquinone mesylate (MitoQ), a synthetic analog of coenzyme Q10 with antioxidant properties, has demonstrated significant improvements in mitochondrial penetration compared to coenzyme Q10, demonstrating potential medicinal benefits. We investigated the effects of MitoQ on neonatal testicular development using ex vivo mouse testicular fragments (MTFs). Methods: Testicular cell differentiation was assessed by culturing MTF from 5-day-old male mice in vitro with 0.01-1 μM MitoQ for 5 days. Cell differentiation, proliferation, and distribution within the testes were assessed using immunohistochemical staining and analysis of gene and protein expression. Results: Histological analysis revealed that 0.01-1 μM MitoQ induced germ cell miogenesis in the seminiferous tubules, increasing the number of Sycp3-positive cells and reducing the genetic expression of the undifferentiated marker Sall4. Sertoli and Leydig cell markers increased at the genetic and protein levels, as confirmed by immunohistochemical staining. In addition, MitoQ increased the expression of antioxidant regulatory and antioxidant enzyme-related factors. Conclusions: Overall, MitoQ can induce the expression of antioxidant factors in in vitro cultured neonatal testes while simultaneously enhancing germ cell differentiation, Sertoli cell proliferation, and Leydig cell maturation and proliferation.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
    Experimental animals and mice testis organ cultures
    Histology and immunostaining
    Western blotting
    Quantitative PCR (qPCR) analysis
    Statistical analyses
RESULTS
    MitoQ enhances germ cell differentiation in in vitroculture of 5-day-old MTFs
    MitoQ affects the increase in Sertoli cell numbers
    MitoQ affects steroidogenesis in Leydig cells
DISCUSSION
CONCLUSION
REFERENCES

• Eun-Jung Kim(Department of Biomedical Laboratory Science, College of Health Sciences, Sangji University, Wonju 26339, Korea)
• Jin-Yeong Kim(Department of Animal Biotechnology, College of Life Science, Sangji University, Wonju 26339, Korea)
• Hyun-Jung Park(Department of Animal Biotechnology, College of Life Science, Sangji University, Wonju 26339, Korea) Corresponding author
• Ran Lee(Department of Animal Biotechnology, College of Life Science, Sangji University, Wonju 26339, Korea, Department of Livestock, Korea National University of Agriculure and Fisheries, Jeonju 54874, Korea)
• Won-Young Lee(Department of Livestock, Korea National University of Agriculure and Fisheries, Jeonju 54874, Korea) Corresponding author