Effect of Sijunzi Decoction on the Myonuclear Domain of Rat Soleus in Spleen Qi Deficiency

Objective: To study the mechanism of Sijunzi decoction treating limb weakness in spleen Qi deficiency (SQD) based on the myonuclear domain (MND) theory. Methods: 40 male Sprague-Dawley rats were randomly divided into the normal group, SQD model group (model group), SQD+ still water group (SW group) and SQD+ Sijunzi decoction group (CM group), 10 rats each group;Grip-Strength Meter was used to measure limb grip strength;transmission electron microscope was employed to observe the ultrastructural changes of the myofibers, Image Pro 6.0 was used to measure the myonuclear numbers, cross-section area (CSA) and then their ratios (the MND sizes) were calculated, immunofluorescence assay was chosen to test the expressions of paired box gene 7 (Pax7) and myogenic differentiation antigen (MyoD). Results: Compared with those in the normal group, limb grip strength was decreased, sarcomeres were abnormal, and all the myonuclear numbers, CSA and MND sizes were reduced, but the Pax7+ cell numbers were increased, significantly, in the model and SW groups;Compared with those in the model and SW groups, limb grip strength was increased, sarcomeres were basically normal, the myonuclear number and CSA were both greater, and the Pax7+ and MyoD+ cell numbers were both increased, significantly, in the CM group. Conclusion: Sijunzi decoction might increase the myonuclear number by activating the MSCs to treat limb weakness in SQD.

Skeletal Muscle Fiber Type and Morphology in a Middle-Aged Elite Male Powerlifter Using Anabolic Steroids

Powerlifting regularly exposes athletes to extreme stimuli such as chronic heavy resistance training(HRT),and many powerlifters choose to augment their performance with anabolic-androgenic steroids(AAS).However,little is known about the myocellular adaptations that occur from long-term HRT and AAS use,especially into middle age.We were presented with the unique opportunity to study muscle cells from an elite-level powerlifter(EPL;age 40 years)with≥30 years of HRT experience and≥15 years of AAS use.The purpose of this case study was to identify myocellular characteristics[myosin heavy chain(MHC)fiber type,fiber size,and myonuclear content]in EPL,as well as compare these data to existing litera-ture.The participant underwent a resting vastus lateralis muscle biopsy and single fibers were analyzed for MHC content via SDS-PAGE.A subset of fibers underwent MHC-specific imaging analysis via confocal microscopy to identify cell size(cross-sectional area,CSA)and myonuclear domain(MND)size.MHC fiber type distribution was 9% I,12% I/IIa,79% IIa,and 0% other isoforms.This pure MHC IIa(fast-twitch)fiber content was amongst the highest reported in the literature.Imaging analysis of MHC IIa fibers revealed a mean CSA of 4218±933μm^(2) and MND of 12,548±3181μm^(3).While the fast-twitch fiber CSA was comparable to values in previous literature,mean MND was smaller than has been reported in untrained men,implying greater capacity for growth and repair.These findings showcase the unique muscle cell structure of an elite powerlifter,extending the known physiological limits of human muscle size and strength.