Effects provoked by chronic undernourishment on the fibre type composition and contractility of fast muscles in male and female developing rats |
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| Authors: | J Pereyra‐Venegas B Segura‐Alegría J C Guadarrama‐Olmos S Mariscal‐Tovar S Quiróz‐González I Jiménez‐Estrada |
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| Institution: | 1. Departamento de Biología, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla de Baz, Estado de México, México;2. Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México;3. Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, San Pedro Zacatenco, México City, México;4. Departamento de Acupuntura y Rehabilitación, Universidad Estatal del Valle de Ecatepec, Valle de Anáhuac, Ecatepec, Estado de México, México |
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| Abstract: | In this study, we compare the effects of pre‐ and post‐natal food deprivation on the relative proportion of fibre types and contractile responses in the extensor digitorum longus (EDL) muscle of female and male rats at different post‐natal ages. EDL muscles from undernourished male (UM) rats showed a higher proportion of Type IIB than IIA fibres and larger normalized twitch responses (with respect to muscle weight) than those of controls (CM). In contrast, EDL muscles from control (CF) and undernourished female rats (UF) showed no significant differences in their fibre type composition and normalized twitch forces at most of the ages analysed. Our data are indicative that the EDL muscles from undernourished males are more susceptible to the effects exerted by low food income than the EDL muscles from female rats. It is proposed that changes in the reactive oxygen species (ROS) concentration and hormonal factors, due to undernutrition, are involved in the alterations observed in the fibre type composition and force production of EDL muscles in undernourished male rats and that estrogens may have an antioxidant protective role on the undernourished EDL muscles in female rats. |
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| Keywords: | contractility muscle fibres gender undernutrition development |
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