Study On Protective Effect Of Compound Ⅰ And Ⅱ On The Disuse Muscle Atrophy And Their Mechanism

Background: A lot of clinical data and animal experiments show that inactivationi immobilization or muscle unloading all can lead to obvious disuse atrophy in skeletal muscles. Therefore, one of the most important and urgent issues to be solved in clinical medicine, sports medicine, rehabilitation medicine and space medicine is to discover some effective medicine for the prevention and treatment of muscle atrophy. Although many researches have been done, they used to focus on the structural, functional as well as biochemical metabolic changes in extrafusal fibres in disuse state. As for the medicine development, they also focused on the effects of them on extrafusal fibres.It has been showed that the afferent discharge of muscle spindle decreases when muscle is in disuse state, which induces or worsens the muscle atrophy. While the afferent discharge of muscle spindle increases, it can prevent or alleviate the muscle atrophy. Moreover, it has been proved that both blood stasis and muscle atrophy could act as cause and result to each other in disuse muscle atrophy. Accordingly, the medicine of invigorating blood circulation that can tingle muscle spindle or increase the afferent discharge of muscle spindle is theoretically the possible ideal drug that prevents and treats the disuse muscle atrophy. Based on the above-mentioned analysis, we confect compound I (ligustrazine et al) and compound II (radix astragali et al) that consist mainly of blood-invigorative medicine, which can distinctively tingle the spontaneous electrical activity of muscle spindle. The hind-limb unloading rat was taken as model to research the morphological structure, biochemical metabolism, hemorrheology of skeletal muscle, so as to provide experimental data for drug development of muscle atrophy.Objective: This research attempts to observe the effects of compound I and compound on disuse muscle atrophy and probes into their mechanism.Methods: Tail-suspended rat was taken as the disuse atrophy model. (1) The rat was treated with compound I and II. The effects of compound I and compound on the structure and ultrastructure of soleus muscle in hind limb unloading rat were studied and compared respectively, by optical microscope, electron microscope and histochemical method. (2) The effects of compound I and compound Ft on the activities of mATPase in tail-suspended rat soleus muscle were observed by histochemical method. (3) Immunohistochemical method was used to study the effects of compound I and compound II of high concentration on immunoreactivity of conjugated-ubiquitin in tail-suspended rat soleus muscle. (4) We observed the effect of I and II of high concentration on hemorrheology by whole blood viscocity, blood plasm viscocity, erythrocyte sedimentation rate, hematocrit value and erythrocyte deformability.Results:(1) Effects of different dosage of compound I and II on the structure and ultrastructure of soleus muscle in hind limb unloading rat1) Compound I and compound of high concentration could effectively prevent weight loss of soleus muscle and decrease of CSA caused by disuse. 2) Compound I and compound II of high concentration could alleviate and slow the changes such as destruction and discontinuity of sarcolemma, destruction and thinning of myofibril and turbulence of Z line and so on. The study suggested the two drugs could prevent the muscle atrophy and alleviate the changes of microstructure and ultrastructure that caused by disuse. The mechanism was involved in the excitement of muscle spindle.(2) Influence of compound I and compound of different dosage on activities of mATPase in hind limb unloading rat soleus muscleThe study showed that compound I and compound of mediate and high concentration effectively prevented the increase of mATPase activities caused by disuse in soleus fibres, and restrained the transformation from slow-twitch muscle to fast-twitch muscle. The results suggested that the two drugs restrained the metabolism changes of muscle fibres in disuse state. Consequently, they can prevent the occurrenceand development of disuse muscle atrophy.(3) Effects of compound I and compound n of high concentration on immunoreactivity of conjugated-ubiquitin in hind limb unloading rat soleus muscle1) Different from the slight expression of conjugated-ubiquitin of soleus muscle in the control group, the expression of conjugated-ubiquitin of rat soleus muscle distinctly increased after 3d, 7d and 14d suspension. 2) After 3 days drug treatment, the expression of conjugated-ubiquitin of rat soleus muscle in the two drug groups was no difference with that of the corresponding experimental suspension groups (P>0.05). 3) After 7 days drug treatment, the expression of conjugated-ubiquitin of rat soleus muscle in the two drug groups became weaker and the proportion of positive fibres was lower than that of the corresponding experimental suspension groups (PO.01). 4) After treatment of the two drugs for 14 days, the expression of conjugated-ubiquitin of rat soleus muscle in the two drug groups was weaker and the proportion of positive fibres was lower than that of the corresponding experimental suspension groups (PO.OOl). The results indicated that the function of anti-disuse muscle atrophy of two drugs was realized by restriction of protein degradation in skeletal muscle.(4) Effects of I and II of high concentration on hemorrheology of hind limb unloading ratAfter 14d hind limb unloading, the whole blood viscocity, blood plasm viscocity, erythrocyte sedimentation rate, hematocrit value and erythrocyte deformability of rat increased significantly. After treatment with I and FI of high concentration for 14 days, the rise of them was obviously under control. The results showed that one of the mechanisms of anti- muscle atrophy of compound I and compound II was possibly realized by improving the red blood cell mass and promoting blood circulation.Conclusion:(1) Compound I and compound FI of high concentration could prevent the weight loss of rat soleus muscle, decrease of CSA and changes of microstructure and ultrastructure in muscle fibres caused by disuse.(2) Compound I and compound II of high concentration could effectively suppress the increase of mATPase activities caused by disuse in skeletal muscle fibres.(3) The immunoreactivity of rat soleus muscle increased remarkably after hind limb unloading. Compound I and compound II of high concentration could remarkably restrain the increase of conjugated-ubiquitin expression caused by disuse.(4) Compound I and compound II of high concentration could drastically inhibit the change of hemorrheology caused by disuse.