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La vitamina B12 apoya la capacidad de fosforilación oxidativa del músculo esquelético en ratones machos
bioRxiv : the preprint server for biology
|September 5, 2025
Resumen
La deficiencia de vitamina B12 provoca la acumulación de uracilo en el ADN mitocondrial y perjudica la función del músculo esquelético. La suplementación mejoró la producción de energía en ratones envejecidos, destacando la vitamina B12
Área de la Ciencia:
- Biología mitocondrial
- La bioquímica nutricional
- Genética molecular
Sus antecedentes:
- La vitamina B12 es crucial para el metabolismo de un carbono mediado por folato (FOCM), que afecta la síntesis de nucleótidos.
- La FOCM deteriorada conduce a la acumulación de uracilo en el ADN, particularmente sensible en el ADN mitocondrial (mtDNA).
- Las consecuencias funcionales del uracil en el ADNmt y los efectos de la deficiencia de B12 en el músculo esquelético no se comprenden bien.
Objetivo del estudio:
- Investigar cómo la deficiencia funcional y dietética de vitamina B12 afecta la integridad del ADNmt y la función mitocondrial en el músculo esquelético.
- Determinar el impacto de la deficiencia de vitamina B12 en el contenido de uracil y la fosforilación oxidativa en el tejido muscular.
Principales métodos:
- Se utilizó Mtr+/- en ratones con deficiencia funcional de vitamina B12 y dietas con deficiencia de vitamina B12 en ratones.
- Suplementación de vitamina B12 administrada a ratones envejecidos.
- Peso muscular estimado, contenido de uracilo en ADNmt, contenido de ADNmt y capacidad del complejo de fosforilación oxidativa.
Principales resultados:
- Los ratones Mtr+/- mostraron una reducción de la capacidad respiratoria máxima en el músculo tibial anterior.
- La dieta con deficiencia de B12 aumentó los niveles de uracilo en el ADNmt (~10 veces) y disminuyó la capacidad del complejo I en el músculo esquelético rojo.
- La suplementación con B12 aumentó la actividad intravenosa compleja en el gastrocnemio de ratones envejecidos.
Conclusiones:
- La deficiencia de vitamina B12 en la dieta induce la acumulación de uracilo en el ADNmt y perjudica la capacidad oxidativa del músculo esquelético.
- La deficiencia de B12 afecta la función mitocondrial en los tejidos que consumen mucha energía.
- La suplementación de vitamina B12 puede restaurar la función mitocondrial en tipos específicos de músculo.
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