[Alterations of myocardial ultrastructure and gene expression of calcium handling proteins in diabetic rat heart].
To investigate the ultrastructure of myocardium and gene expression of calcium handling proteins in diabetic rat heart.



Diabetes was induced in male Sprague-Dawley rats by a single injection of alloxanm (40 mg/kg ) and the rats in control group were injected with normal saline. At the end of 2, 4, 6 weeks after the induction of diabetes, the animals were sacrificed. The expression of calcium handling proteins was detected by reverse transcription-polymerase chain reaction (RT-PCR) and actin mRNA was used as internal standard. Heart tissue at the apex was obtained for light and electron microscope study.



At the end of 4 and 6 weeks, cardiosomatic ratio of diabetic rats was higher than that of control. Electron microscopy revealed a spectrum of subcellular remodeling in myocardium which was characterized by damaged myofibrils and mitochondria, dilated and swollen sarcoplasmic reticulum. Expression of phospholamban mRNAs was significantly increased, but 1,4,5-trisphosphate inositol receptor type 2, ryanodine receptor type 2 mRNAs were significantly decreased compared with those in the age-matched control rats. In contrast, the expression of sarco/endoplasmic reticulum Ca(2+)-ATPase mRNAs was not affected.



In diabetic rat heart, gene expression of calcium handling proteins was characterized by up-regulation of phospholamban and down-regulation of sarcoplasmic reticulum calcium release channel while electron microscopic analysis of myocardium revealed a spectrum of subcellular remodeling.
Zhou
Bin-quan
BQ
Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, China.
Hu
Shen-jiang
SJ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology*; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012519:Sarcoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D000099211:Phospholamban
D002118:Calcium; D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D012333:RNA, Messenger; D000099211:Phospholamban