The Experimental Study Of The Effect Of Xiaoyingqiangjitang On Cardiac Muscle Disease Related To Hyperthyroidism

Objectives: To establish an animal experimental model of hyperthyroidism relatedmuscle disease by giving L-thyroxine sodium salt (T₃) intraperitoneally to the healthyfemale Wistar rats. Xiaoyingqiangjitang was given to the stomach of rats throughinjecting. The morphological changes of cardiac muscle were observed under light andelectron microscopy. Changes in body weight, heart rate and the level of serum T3,T4were noted. Heart index and heart plump index of the three groups were measured.SOD,GPX and MDA of cardiac muscles were estimated by enzymology method.Methods: The thirty healthy female rats were randomly divided into three groups:groupâ… : receiving intraperitoneal injection of L-thyroxine sodium salt, 250μg/1ml,1ml/100g BW once a day for 40 days; groupâ…¡: receiving intraperitoneal injection ofL-thyroxine sodium salt, 250μg/1ml, 1ml/100g BW once a day for 40 days andxiaoyingqiangjitang for 40 days at the same time; groupâ…¢: normal healthy rats receivingsaline solution only as control. Then the cardiac muscle were removed and processed byfollowing procedures: Some specimens were made into paraffin section, stained byhematoxylin-eosin(HE) staining method and morphological changes were observed bylight microscope; Some specimens were prepared into transmission electron microscope(TEM) sample and the effect of xiaoyingqiangjitang on cardiac muscle ultrastructuralalteration was observed by TEM. For enzyme cytochemistry, other specimens were madeinto homogenate for the measurement of SOD,GPX and MDA. The level of serumT3,T4 was detected by radioimmunity method. The heart indexes for HW/BW,LVW/BW,LVWT and VST were measured.Results: (1) The average body weight of groupâ… declined gradually with a obviousrage, but the rage in the groupâ…¡was much less. The heart rate showed the same chang.(2)The level of T3,T4 in the groupâ…¡was increased compared with the groupâ…¢, butdecreased compared with the groupâ…¢(P＜0.01). (3) The heart indexes showed: TheHW/BW,LVW/BW,LVWT and VST of groupâ… andâ…¡were increased compared withthe groupâ…¢(P＜0.01),but the indexes in the groupâ…¡were decreased compared with thegroupâ… . (4) The results of enzyme cytochemistry showed: The activity of SOD and GPXin groupâ…¡were increased compared with the groupâ… (P＜0.01). And that of MDA wasdecreased compared with the groupâ… (P＜0.05). (5) Light microscope observation shows:there were more abnormalities found in groupâ… : the space between fibers become slightwiden, the cross striation become faint. Muscle fibers were alternate. After givien chinesemedcine, all abnormities disappeared basically. There were no obviously increasing ofconnective tissue between myofibers in the groupâ…¡, but the increase of connective tissuebetween myofibers in the groupâ… were apparent. After given chinese medicine, thechanges were greatly improved. (6) Under TEM, we found that the myofilaments inT3-treated groups arranged irregularly, some vacuole could be observed, Some sarcomere shorten. Some mitochondria swelled, some lengthened. For 42days, the cristaeof mitochondria ruptured, inosculated and even disappeared and some mitochondriabecame bulgy and nonuniformed size. The nuclears were irregular and the thickness ofkaryotheca was nonuniformity. The chromatic agglutination was keeping to the sideand the plaque form under the karyotheca. After using of the T3, the alterations ofultrastructure in the two groups were all mended greatly. Most changes occurred inmitochondria.Conclusions: (1) With the body weight decreasing obviously, the heart rateincreasing obviously and the obvious hyperthyroidism symptoms, we established thehyperthyroidism animal model susccessfully. (3) The structural changes of cardiacmuscle were observed by light and electron microscope when the thyroxine is high for along time. After intraperitonealed Chinese medicine, the structural changes wereimproved greatly contrasted to control group of intraperitonealing sodium salt. Thisshowed that xiaoyingqiangjitan had protective effect on the cardiac muscle from highlevel of thyroid hormone. (2) Hypertrophic cardiomyopathy may be caused by manydirect and indirect factors, the high level of thyroid hormone is the fundamentally reason.(4) Overdose thyroxine could decrease the activity of SOD and GPX of cardiac musclewith MDA increasing, xiaoyingqiangjitan could effectively increase the activity of SODand GPX of cardiac muscle with MDA decreasing. This showed xiaoyingqiangjitancould enhance the antioxidation action of cardiac muscle and protect the cardiac musclefrom harmed by OFR. Probably this is also the mechanism for xiaoyingqiangjitan toprevent cardiac muscle of hyperthyroidism rat from hypertrophic cardiomyopathy.