Prolonged Immobilization Exacerbates the Loss of Muscle Mass and Function Induced by Cancer-Associated Cachexia through Enhanced Proteolysis in Mice

Abstract

We hypothesized that in mice with lung cancer (LC)-induced cachexia, periods of immobilization of the hindlimb (7 and 15 days) may further aggravate the process of muscle mass loss and function. Mice were divided into seven groups (n = 10/group): (1) non-immobilized control mice, (2) 7-day unloaded mice (7-day I), (3) 15-day unloaded mice (15-day I), (4) 21-day LC-cachexia group (LC 21-days), (5) 30-day LC-cachexia group (LC 30-days), (6) 21-day LC-cachexia group besides 7 days of unloading (LC 21-days + 7-day I), (7) 30-day LC-cachexia group besides 15 days of unloading (LC 30-days + 15-day I). Physiological parameters, body weight, muscle and tumor weights, phenotype and morphometry, muscle damage (including troponin I), proteolytic and autophagy markers, and muscle regeneration markers were identified in gastrocnemius muscle. In LC-induced cachexia mice exposed to hindlimb unloading, gastrocnemius weight, limb strength, fast-twitch myofiber cross-sectional area, and muscle regeneration markers significantly decreased, while tumor weight and area, muscle damage (troponin), and proteolytic and autophagy markers increased. In gastrocnemius of cancer-cachectic mice exposed to unloading, severe muscle atrophy and impaired function was observed along with increased muscle proteolysis and autophagy, muscle damage, and impaired muscle regeneration.

Curcumin and Resveratrol Improve Muscle Function and Structure through Attenuation of Proteolytic Markers in Experimental Cancer-Induced Cachexia

“…The cell line was validated for its characteristics as an identical tumor developer, tumor incidence, pathological features, and the potential to induce cachexia, like its progenitor P07 tumor [ 3 , 29 , 30 , 31 ]. The model used in the current study has been extensively validated [ 3 , 7 , 28 , 31 ]. Resveratrol was purchased from Fagron Ibérica (Terrassa, Barcelona, Spain): molecular weight 228.2 g, C 14 H 12 O 3 , 98.6% purity, and the trans conformation was used.…”

“…Ten-week-old female BALB/c mice (weight ~20 g) were acquired from Harlan Interfauna Iberica SL (Barcelona, Spain). Female mice were used for practical reasons, since most investigations have also been carried out in this type of rodent in our group [ 3 , 7 , 15 , 27 , 28 , 29 ].…”

“…Moreover, also for ethical reasons, a nontumor control group of mice was not included in the investigation. Differences between nontumor animals and tumor-bearing mice have been extensively described in this model of lung cancer-induced cachexia [ 3 , 7 , 28 , 31 ].…”

“…In all the animals, grip strength was quantified using a grip strength meter (Bioseb, Vitrolles, France). Plasma samples were extracted on day 0, on day 15 before starting the different treatments, and on day 30, right before the sacrifice of the mice [ 3 , 15 , 27 , 28 , 29 , 31 ]. Limb strength and total body weight gains were calculated as the percentage of the measurements obtained on day 30 with respect to baseline measurements (day 0) [ 3 , 15 , 27 , 28 , 29 , 31 ].…”

“…A group of cancer cachectic mice that received no treatment with any of the polyphenolic compounds was used as the control animals. Female mice were used for the sake of consistency with previously reported results in our group [ 3 , 7 , 15 , 27 , 28 , 29 ]. Specifically, trans-resveratrol was used in the current investigation.…”