[Purpose] This study aimed to develop a VO2peak-based framework for classifying exercise intensity in ICR mice and to validate the associated physiological responses.[Methods] Male ICR mice (8 weeks) completed four maximal graded exercise test (GXT) protocols (P1–P4) using a treadmill-equipped metabolic chamber. P1 and P2 began at 10 m/min with a fixed 15° incline, increasing speed by 3 m/min every 3 min (P1) or 1.5 m/min every 1.5 min (P2). P3 and P4 also started at 10 m/min but from a 0° incline; P3 increased both speed (3 m/min every 3 min) and incline (3° every 3 min), while P4 increased speed (1.5 m/min every 1.5 min) and incline (1.5° every 1.5 min) until 15°, after which only speed increments continued. VO2peak values were then used to calculate running speeds at 40%, 60%, and 80% VO2reserve to represent low, moderate, and high intensity, respectively. Constant-load tests (CXT) at these speeds measured metabolic responses and blood lactate concentrations.[Results] VO2peak did not differ significantly among protocols, but P4 showed greater variability. Target speeds were therefore determined from P1–P3. During CXT, oxygen consumption, energy expenditure, and VO2plateau rose with intensity, and blood lactate at 60% and 80% VO2reserve exceeded that at 40%, with 60% surpassing the 4 mM aerobic–anaerobic threshold.[Conclusion] These findings provide standardized VO2peak-based reference values for classifying exercise intensity in ICR mice. Fixed-incline GXT protocols reduce variability, and the derived speed thresholds can guide future exercise interventions.

Autophagy is an evolutionarily conserved catabolic process for maintaining cellular homeostasis during both normal and stress conditions. Metabolic reprogramming in tissues of dead bodies is inevitable due to chronic ischemia and nutrient deprivation, which are well-known features that stimulate autophagy. Currently, it is not fully elucidated whether postmortem autophagy, also known as thanatophagy, occurs in dead bodies is a function of the time of death. In this study, we tested the hypothesis that thanatophagy would increase in proportion to time elapsed since death for tissues collected from cadavers. Brain and heart tissue from corpses at different time intervals after death were analyzed by Western blot. Densitometry analysis demonstrated that thanatophagy occurred in a manner that was dependent on the time of death. The autophagy-associated proteins, LC3 II, p62, Beclin-1 and Atg7, increased in a time-dependent manner in heart tissues. A potent inducer of autophagy, BNIP3, decreased in the heart tissues as time of death increased, whereas the protein levels increased in brain tissues. However, there was no expression of BNIP3 at extended postmortem intervals in both brain and heart samples. Collectively, the present study demonstrates for the first time that thanatophagy occurs in brain and heart tissues of cadavers in a time-dependent manner. Further, our data suggest that cerebral thanatophagy may occur in a Beclin-1- independent manner. This unprecedented study provides potential insight into thanatophagy as a novel method for the estimation of the time of death in criminal investigations Autophagy is an evolutionarily conserved catabolic process for maintaining cellular homeostasis during both normal and stress conditions. Metabolic reprogramming in tissues of dead bodies is inevitable due to chronic ischemia and nutrient deprivation, which are well-known features that stimulate autophagy. Currently, it is not fully elucidated whether postmortem autophagy, also known as thanatophagy, occurs in dead bodies is a function of the time of death. In this study, we tested the hypothesis that thanatophagy would increase in proportion to time elapsed since death for tissues collected from cadavers. Brain and heart tissue from corpses at different time intervals after death were analyzed by Western blot. Densitometry analysis demonstrated that thanatophagy occurred in a manner that was dependent on the time of death. The autophagy-associated proteins, LC3 II, p62, Beclin-1 and Atg7, increased in a time-dependent manner in heart tissues. A potent inducer of autophagy, BNIP3, decreased in the heart tissues as time of death increased, whereas the protein levels increased in brain tissues. However, there was no expression of BNIP3 at extended postmortem intervals in both brain and heart samples. Collectively, the present study demonstrates for the first time that thanatophagy occurs in brain and heart tissues of cadavers in a time-dependent manner. Further, our data suggest that cerebral thanatophagy may occur in a Beclin-1- independent manner. This unprecedented study provides potential insight into thanatophagy as a novel method for the estimation of the time of death in criminal investigations

[Purpose] Skeletal muscles have notable features that enable muscle hypertrophy in response to resistance training (RET). Most animal studies on ladder climbing have focused on the lower limb muscles; however, the movement also involves the upper limb muscles. Moreover, little evidence exists regarding whether RET affects food intake. Therefore, this study aimed to investigate RET-induced muscle hypertrophy in both the upper and lower limb muscles and to examine changes in food intake.[Methods] Twenty male Wistar Hannover rats (6 weeks old) were randomly assigned to sedentary control (SED, n = 10) or resistance training (RET, n = 10) groups during a 2-week acclimatization period. RET rats underwent the primary exercise training for 8 weeks, after 1 week of climbing adaptation, with a one-repetition maximum test. Body weight and food intake were monitored weekly. Twenty-four hours after the final training session, major muscles were dissected and weighed, and the flexor digitorum profundus (FDP) was analyzed using the cross-sectional area (CSA) of the myofibers.[Results] RET group showed significantly decreased final body weight and food intake compared to the SED group (p < 0.001). RET enhanced both muscle quantity (increased relative FDP muscle weight) and quality (improved muscle strength capacity and larger FDP myofibers).[Conclusion] Ladder-climbing RET induced hypertrophy in the upper limb FDP muscle rather than in other lower limb muscles despite decreases in body weight and food intake. Upper extremity strength training can provide benefits to healthy adults and individuals with limited lower extremity mobility.

Background/Objectives: Alternate-day fasting (ADF) combined with exercise has been suggested as an effective lifestyle strategy for reducing fat mass while preserving lean mass. However, whether exercise preconditioning before ADF plus concurrent exercise affects subsequent body-composition and substrate-utilization responses remains unclear. This study aimed to evaluate the effects of exercise preconditioning during a subsequent ADF plus concurrent exercise intervention. Methods: Seven-week-old male ICR mice were assigned to the non-exercise preconditioning (Non-ExPC) or exercise preconditioning (ExPC) group (n = 8/group). After the 4-week preconditioning period, both groups underwent 7 days of ADF plus concurrent exercise. Resting energy metabolism was measured during the intervention, and body composition, exercise energy metabolism, muscle and motor function, blood biomarker concentrations, and plasma hormone levels were assessed before and after the intervention. Results: Both groups showed significant reductions in body weight, body fat percentage, and fat mass after the intervention. Lean mass decreased in both groups without between-group differences. The ExPC group maintained significantly lower body fat percentage and fat mass than the Non-ExPC group and showed significantly higher resting oxygen uptake, carbon dioxide production, respiratory exchange ratio, carbohydrate oxidation, and energy expenditure during the intervention. During exercise, the respiratory exchange ratio and carbohydrate oxidation significantly increased in both groups, whereas fat oxidation significantly decreased only in the ExPC group. Conclusions: Exercise preconditioning was associated with the maintenance of lower adiposity during short-term ADF combined with concurrent exercise, while differences in substrate utilization were observed under some conditions.