We examined the effect of a combination of astaxanthin （AX） supplementation, repeated heat stress, and intermittent reloading （IR） on satellite cells in unloaded rat soleus muscles. Forty-nine male Wistar rats （8...We examined the effect of a combination of astaxanthin （AX） supplementation, repeated heat stress, and intermittent reloading （IR） on satellite cells in unloaded rat soleus muscles. Forty-nine male Wistar rats （8-week-old） were divided into control, hind-limb unweighting （HU）, IR during HU, IR with AX supplementation, IR with repeated heat stress （41.0-41.5 ℃ for 30 min）, and IR with AX supplementation and repeated heat stress groups. After the experimental period, the antigravitational soleus muscle was analyzed using an immunohistochemical technique. Our results revealed that the combination of dietary AX supplementation and heat stress resulted in protection against disuse muscle atrophy in the soteus muscle. This protective effect may be partially due to a higher satellite cell number in the atrophied soleus muscle in the IR/AX/heat stress group compared with the numbers found in the other groups. We concluded that the combination treatment with dietary AX supplementation and repeated heat stress attenuates soleus muscle atrophy, in part by increasing the number of satellite cells.展开更多
Apoptosis is necessary for maintaining the integrity of proliferative tissues, such as epithelial cells of the gastrointestinal system. The role of apoptosis in post mitotic tissues, such as skeletal muscle, is less w...Apoptosis is necessary for maintaining the integrity of proliferative tissues, such as epithelial cells of the gastrointestinal system. The role of apoptosis in post mitotic tissues, such as skeletal muscle, is less well defined. Apoptosis during muscle atrophy occurs in both myonuclei and other muscle cell types. Apoptosis of myonuclei likely contributes to the loss of muscle mass, but the mechanisms underlying this process are largely unknown. Caspase-dependent as well as -independent pathways have been implicated and the mode by which atrophy is induced likely determines the apoptotic mechanisms that are utilized. It remains to be determined whether a decrease in apoptosis will alleviate atrophy and distinct research strategies may be required for different causes of skeletal muscle loss.展开更多
Objective In drugs for i nvigorating blood circulation, to find a herb that can stimulate afferent discha rge of muscle spindle. Methods A single muscle spindle was isolated from sartorial mus cle of toad. Using ai...Objective In drugs for i nvigorating blood circulation, to find a herb that can stimulate afferent discha rge of muscle spindle. Methods A single muscle spindle was isolated from sartorial mus cle of toad. Using air-gap technique, afferent discharge of the muscle spindle was recorded. Effects of Angelica Sinensis, Salvia Miltiorrhiza, and Safflower o n afferent discharge of the muscle spindle were observed. Results Angelica Sinensis could distinctly increase afferent di scharge frequency of the muscle spindle, and this increase was dose-dependent. But Salvia Miltiorrhiza and Safflower had no this excitatory effect. Conclusion It is known that Angelica Sinensis can invigorate bl ood circulation, and we have found its excitatory effect on muscle spindle which makes it possible to serve people with muscle atrophy if more evidences from cl inical experiments are available.展开更多
Endurance exercise training promotes a protective phenotype in skeletal muscle known as exercise pre-conditioning.Exercise preconditioning protects muscle fibers against a variety of threats including inactivity-induc...Endurance exercise training promotes a protective phenotype in skeletal muscle known as exercise pre-conditioning.Exercise preconditioning protects muscle fibers against a variety of threats including inactivity-induced muscle atrophy.The mechanism(s)responsible for exercise preconditioning remain unknown and are explored in these experiments.Specifically,we investigated the impact of endurance exercise training on key components of the renin-angiotensin system(RAS).The RAS was targeted because activation of the classical axis of the RAS pathway via angiotensinⅡtypeⅠreceptors(AT1Rs)promotes muscle atrophy whereas activation of the non-classical RAS axis via Mas receptors(MasRs)inhibits the atrophic signaling of the classical RAS pathway.Guided by prior studies,we hypothesized that an exercise-induced decrease in AT1Rs and/or increases in MasRs in skeletal muscle fibers is a potential mechanism responsible for exercise preconditioning.Following endurance exercise training in rats,we examined the abundance of AT1Rs and MasRs in both locomotor and respiratory muscles.Our results indicate that endurance exercise training does not alter the protein abundance of AT1Rs or MasRs in muscle fibers from the diaphragm,plantaris,and soleus muscles compared to sedentary controls(p>0.05).Furthermore,fluorescent angiotensinⅡ(AngⅡ)binding analyses confirm our results that exercise pre-conditioning does not alter the protein abundance of AT1Rs in the diaphragm,plantaris,and soleus(p>0.05).This study confirms that exercise-induced changes in RAS receptors are not a key mechanism that contributes to the beneficial effects of exercise preconditioning in skeletal muscle fibers.展开更多
基金Project supported by the Japan Society for the Promotion of Science(JSPS)KA-KENHI(Nos.20500578 and 17K01765)the Ministry of Education,Culture,Sports,Science and Technology(MEXT)-Supported Program for the Strategic Research Foundation at Private Universities
文摘We examined the effect of a combination of astaxanthin （AX） supplementation, repeated heat stress, and intermittent reloading （IR） on satellite cells in unloaded rat soleus muscles. Forty-nine male Wistar rats （8-week-old） were divided into control, hind-limb unweighting （HU）, IR during HU, IR with AX supplementation, IR with repeated heat stress （41.0-41.5 ℃ for 30 min）, and IR with AX supplementation and repeated heat stress groups. After the experimental period, the antigravitational soleus muscle was analyzed using an immunohistochemical technique. Our results revealed that the combination of dietary AX supplementation and heat stress resulted in protection against disuse muscle atrophy in the soteus muscle. This protective effect may be partially due to a higher satellite cell number in the atrophied soleus muscle in the IR/AX/heat stress group compared with the numbers found in the other groups. We concluded that the combination treatment with dietary AX supplementation and repeated heat stress attenuates soleus muscle atrophy, in part by increasing the number of satellite cells.
基金Supported by NIH/NIA, No.AG20407 NIH/NIAMS, No. AR47577
文摘Apoptosis is necessary for maintaining the integrity of proliferative tissues, such as epithelial cells of the gastrointestinal system. The role of apoptosis in post mitotic tissues, such as skeletal muscle, is less well defined. Apoptosis during muscle atrophy occurs in both myonuclei and other muscle cell types. Apoptosis of myonuclei likely contributes to the loss of muscle mass, but the mechanisms underlying this process are largely unknown. Caspase-dependent as well as -independent pathways have been implicated and the mode by which atrophy is induced likely determines the apoptotic mechanisms that are utilized. It remains to be determined whether a decrease in apoptosis will alleviate atrophy and distinct research strategies may be required for different causes of skeletal muscle loss.
文摘Objective In drugs for i nvigorating blood circulation, to find a herb that can stimulate afferent discha rge of muscle spindle. Methods A single muscle spindle was isolated from sartorial mus cle of toad. Using air-gap technique, afferent discharge of the muscle spindle was recorded. Effects of Angelica Sinensis, Salvia Miltiorrhiza, and Safflower o n afferent discharge of the muscle spindle were observed. Results Angelica Sinensis could distinctly increase afferent di scharge frequency of the muscle spindle, and this increase was dose-dependent. But Salvia Miltiorrhiza and Safflower had no this excitatory effect. Conclusion It is known that Angelica Sinensis can invigorate bl ood circulation, and we have found its excitatory effect on muscle spindle which makes it possible to serve people with muscle atrophy if more evidences from cl inical experiments are available.
基金the National Institute of Health(R21AR063956 to SKP).
文摘Endurance exercise training promotes a protective phenotype in skeletal muscle known as exercise pre-conditioning.Exercise preconditioning protects muscle fibers against a variety of threats including inactivity-induced muscle atrophy.The mechanism(s)responsible for exercise preconditioning remain unknown and are explored in these experiments.Specifically,we investigated the impact of endurance exercise training on key components of the renin-angiotensin system(RAS).The RAS was targeted because activation of the classical axis of the RAS pathway via angiotensinⅡtypeⅠreceptors(AT1Rs)promotes muscle atrophy whereas activation of the non-classical RAS axis via Mas receptors(MasRs)inhibits the atrophic signaling of the classical RAS pathway.Guided by prior studies,we hypothesized that an exercise-induced decrease in AT1Rs and/or increases in MasRs in skeletal muscle fibers is a potential mechanism responsible for exercise preconditioning.Following endurance exercise training in rats,we examined the abundance of AT1Rs and MasRs in both locomotor and respiratory muscles.Our results indicate that endurance exercise training does not alter the protein abundance of AT1Rs or MasRs in muscle fibers from the diaphragm,plantaris,and soleus muscles compared to sedentary controls(p>0.05).Furthermore,fluorescent angiotensinⅡ(AngⅡ)binding analyses confirm our results that exercise pre-conditioning does not alter the protein abundance of AT1Rs in the diaphragm,plantaris,and soleus(p>0.05).This study confirms that exercise-induced changes in RAS receptors are not a key mechanism that contributes to the beneficial effects of exercise preconditioning in skeletal muscle fibers.
