Effects Of Exercise On Sarcopenia Related Anti-oxidative Capacity & Mitochondria Mediated Apoptotic Signaling Pathway

As the saying goes,aging of human starts from the legs.Sarcopenia is one kindof characters for the aging of legs.Sarcopenia is defined as the gradual reduction ofskeletal muscle mass and strength observed with advancing age.It starts to set inaround age 40,when muscle begins to decline at a rate of about one percent per year;what's more,it deteriorates with profound repercussions after approximately 75 yearsof age.This gradual loss has been tied to protein deficiency,lack of exercise amongthe elderly.This condition strongly influences muscle strength and mobility and is afactor in the occurrence of frailty and likelihood of falls and fractures in the elderly.The world now witnesses an unprecedented trend in population aging,bearingsignificant implications for the healthcare cost problems.Recently,it is reported thatphysical activity has profound effects on the musculoskeletal system,and contributesto the maintenance of functional abilities,and prevents Sarcopenia to some extent.ObjectsThe present study is designed to determine the effects of ladder climbing,treadmill running exercise on Sarcopenia related anti-oxidative capacity andmitochondria mediated apoptotic signaling pathway in Gastrocnemius and Tibialisanterior muscles of Senescence Accelerated Mouse Prone/8 (SAMP8)after 8 or 21weeks of exercise training to better understand the cellular and molecular etiology dueto redox-status and apoptotic signaling pathway,and to advocate the concept of"exercise promotes life expectancy"finally.MethodsThe study here selects male SAMP8 at different month's age as the researchanimal.By taking advantage of the accelerated aging character,ladder climbing andtreadmill running exercise are used to intervene the aging model after 8weeks,21weeks and 8 weeks for 3-month,4-month and 6-month age mice respectively.Ultraviolet-visible detecting method is used to detect the anti-oxidant capacity index,(T-AOC,Total SOD,CAT and MDA);quantitative Real-time PCR method is used todetect key check points and regulating points in Sarcopenia related Caspasedependent and independent apoptotic signaling pathway in Gastrocnemius andTibialis anterior muscles. ResultsThe research indicates that:(1)The Gastrocnemius and Tibialis anterior muscles of SAMP8 mice in old grouphave shown the character of Sarcopenia,and no differences of the body weight arefound among the groups except the elevation of LR group compared with SR group.(2)The anti-oxidant capacity changes diversely in the two kinds of skeletalmuscles during the aging process,with the up-regulation and down-regulation ofGastrocnemius and Tibialis anterior muscle respectively.Most of the check points inthe apoptotic signaling pathway are inclined to prevent both muscles from furtheraging induced by apoptosis.However,Gastrocnemius and Tibialis anterior muscle arestill trending towards apoptosis under the redox status,and complete the apoptosisprocess via up-regulation of Caspase-3.(a)The effects of eight weeks intervene of ladder climbing and treadmill runningon anti-oxidant capacity show differently in Gastrocnemius and Tibialis anteriormuscle of young group of SAMP8 mice,which reveals that different adaptation ofdifferent muscles under different exercise training.Ladder climbing exercise is likelyto weaken the potential for apoptosis via Caspase dependent apoptotic signalingpathway in both muscles,while treadmill running exercise is likely to promoteapoptosis via Caspase independent apoptotic signaling pathway according toup-regulate the expression of AIF.(4)Eight weeks intervene of ladder climbing and treadmill running up-regulateanti-oxidase activities either in Gastrocnemius or Tibialis anterior muscle of old groupof SAMP8 mice,but may influence diversely non-enzymatic antioxidants in bothmuscles,thus altering the result of oxidative damage due to opposite changes of totalanti-oxidant capacity.Even though,eight weeks exercise training of climbing andrunning still attenuate the apoptotic trends of the aging muscles via inhibition ofCaspase dependent and independent apoptotic signaling pathway.(5)Twenty-one weeks intervene of ladder climbing and treadmill running alsoup-regulate anti-oxidase activities either in Gastrocnemius or Tibialis anterior muscleof old group of SAMP8 mice,but the total anti-oxidant capacity still showdown-regulation,thus inducing the different results of oxidative damage for theGastrocnemius or Tibialis anterior muscle.Anyway,the effect of treadmill running onGastrocnemius or Tibialis anterior muscle and the effect of ladder climbing on Tibialisanterior muscle still show the tendency of attenuate the apoptosis potential.Unexpectedly,ladder climbing exercise training promotes apoptosis potential inGastrocnemius of old group and the promotion may be completed by the synergy ofCaspase dependent and AIF mediated Caspase independent pathways.(6)Compared with eight weeks exercise training,twenty-one weeks exercise training have not shown further identical progressive changes with the prolongedintervene time in the index of anti-oxidant capacity,apoptotic check points andregulating points.Conclusions(1)Gastrocnemius and Tibialis anterior muscle of the old group of SAMP8 miceis feasible in the research of Sarcopenia.(2)Different adaptation results exist in different anti-oxidant capacity withdifferent ages under different exercise intervene modes.(3)In both muscles of young group,eight weeks ladder climbing is prone toattenuate apoptosis potential via down-regulation of Caspase-3,while treadmillrunning exercise training is prone to promote apoptosis via up-regulation of AIF.(4)Eight weeks ladder climbing and treadmill running exercise training arepossibly to attenuate the apoptosis potential in Gastrocnemius and Tibialis anteriormuscle of old group.(5)Twenty-one weeks ladder climbing and treadmill running exercise training arepossibly to attenuate the apoptosis potential in Gastrocnemius and Tibialis anteriormuscle of old group,only except the promoting effect of ladder climbing exercise onaged Gastrocnemius.(6)Compared with eight weeks exercise training,twenty-one weeks exercisetraining have not shown further identical progressive changes with the prolongedintervene time in the index of anti-oxidant capacity,apoptotic check points andregulating points.Taken all together,the effects of ladder climbing and treadmill running exercisetraining on Sarcopenia related anti-oxidant capacity and apoptotic signaling pathwayare different to some extent in the muscles of young group and old group of SAMP8mice.Nevertheless,either promoting or attenuating effect is the fate of adaptation ofskeletal muscles after competition.