Soluble Milk Protein Supplementation with Moderate Physical Activity Improves Locomotion Function in Aging Rats

Abstract

Aging is associated with a loss of muscle mass and functional capacity. Present study was designed to compare the impact of specific dairy proteins on muscular function with or without a low-intensity physical activity program on a treadmill in an aged rat model. We investigated the effects of nutritional supplementation, five days a week over a 2-month period with a slow digestible protein, casein or fast digestible proteins, whey or soluble milk protein, on strength and locomotor parameters in sedentary or active aged Wistar RjHan rats (17–19 months of age). An extensive gait analysis was performed before and after protein supplementation. After two months of protein administration and activity program, muscle force was evaluated using a grip test, spontaneous activity using an open-field and muscular mass by specific muscle sampling. When aged rats were supplemented with proteins without exercise, only minor effects of different diets on muscle mass and locomotion were observed: higher muscle mass in the casein group and improvement of stride frequencies with soluble milk protein. By contrast, supplementation with soluble milk protein just after physical activity was more effective at improving overall skeletal muscle function in old rats compared to casein. For active old rats supplemented with soluble milk protein, an increase in locomotor activity in the open field and an enhancement of static and dynamic gait parameters compared to active groups supplemented with casein or whey were observed without any differences in muscle mass and forelimb strength. These results suggest that consumption of soluble milk protein as a bolus immediately after a low intensity physical activity may be a suitable nutritional intervention to prevent decline in locomotion in aged rats and strengthen the interest to analyze the longitudinal aspect of locomotion in aged rodents.

Pregnancies alters spine number in cortical and subcortical limbic brain regions of old rats

“…According to the current data, several reports showed that aging caused a reduction in physical activity, including locomotor activity in a novel environment in rodents and humans (Ayers & Verghese, ; Ingram & Jucker, ; Lafoux, Baudry, Bonhomme, Ruyet, & Huchet, ; Yu, Xu, Song, Ji, & Zhang, ). Additionally, some reports have suggested a reduction in spinogenesis and in dendritic length in aged animals (Alcántara‐González et al, , ; Cabrera‐Pedraza et al, ; Diaz et al, ; Hernández‐Hernández et al, ; Juárez et al, ; Sánchez et al, ; Solis‐Gaspar, Vazquez‐Roque, Jesús Gómez‐Villalobos, & Flores, ; Vidal et al, ; Xu et al, ).…”

“…As we mention before, it is well known that aged rats show a reduction in physical activity, including locomotor activity in a novel environment (Ingram & Jucker, ; Lafoux et al, ; Yu et al, ). Accordingly, an increase in locomotor activity in a novel environment may suggest a behavioral improvement.…”

Physical Exercise After Immobilization of Skeletal Muscle of Adult and Aged Rats

“…The present study demonstrated that after seven days of immobilization, muscle disuse promoted significant atrophy of muscle tissue, both in adult (five months) and elderly animals (15 months), 3,10 and that exercise was able to reverse this harmful effect in a seven day exercise intervention in adult animals, however in the elderly animals, seven days of exercise were not enough to reverse the process of muscle atrophy.…”

Phenylbutyrate ameliorates prefrontal cortex, hippocampus, and nucleus accumbens neural atrophy as well as synaptophysin and GFAP stress in aging mice

“…Previous reports have shown that aging caused a reduction in locomotor activity (Flores‐Vivaldo et al., 2019; Insgrama & Jucker, 1999; Lafoux, Baudry, Bonhomme, Le Ruyet, & Huchet, 2016; Yu, Xu, Song, Ji, & Zhang, 2013). For this reason, we analyzed whether the PBA has an effect on this type of behavior.…”

“…This cognitive improvement was not related to an increase in locomotor activity in a new environment. It is also well‐known that, like cognition, locomotive activity is also reduced with aging (Alcantara‐González et al, 2012; Flores‐Vivaldo et al., 2019; Insgrama & Jucker, 1999; Lafoux et al., 2016; Yu et al., 2013). However, our results suggest that the PBA did not modify locomotive activity in a novel environment in the old mice, despite producing an improvement in the number of dendritic spines and markers for synaptophysin without changes in the total dendritic length in the NAcc, a structure related to this behavior.…”