title: [Diaphragm dysfunction and expressions of calcium regulatory proteins in diabetic rats].
abstract: OBJECTIVE
  To study the changes in diaphragmatic function and gene expressions of calcium regulatory proteins in diabetic rats and explore the mechanism of diaphragm dysfunction in diabetes mellitus.
  
  
  METHODS
  SD rats were randomly divided into normal control group and diabetic (induced by intraperitoneal STZ injection) group. After 4 and 8 weeks, the body weight and diaphragm to body weight ratio were measured, and the activities of succinic dehydrogenase (SDH) in the diaphragm and blood glucose were assayed. The diaphragm contractility was assessed and the alterations of diaphragm ultrastructure were observed. RT-PCR was used to detect the changes in sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) and phospholamban (PLB) mRNA expressions in the diaphragm.
  
  
  RESULTS
  The diabetic rats showed a significant weight loss with a lowered diaphragm to body weight ratio (P<0.01) and SDH activity (P<0.01). The peak twitch tension and maximum tetanic tension of the diaphragm were significantly lowered and the time to peak contraction and half relaxation time significantly prolonged (P<0.01) in the diabetic rats, which also exhibited a lowered tetanic force in response to stimulus (P<0.01). Transmission electron microscopy revealed obvious ultrastructural changes of the diaphragm in diabetic rats. RT-PCR showed significantly decreased SERCA and increased PLB mRNA expressions in diabetic rat diaphragm (P<0.01), and these changes intensified with time (P<0.01).
  
  
  CONCLUSIONS
  Diabetes can cause impairment of diaphragmatic ultrastructure, mitochondrial injuries, and lowered SDH activity and ATP production. Decreased SERCA and increased PLB mRNA expressions in diabetes result in reduced Ca(2+) uptake by the diaphragm sarcoplasmic reticulum to induce diaphragm dysfunction.
authors: Department of Physiology, Bengbu Medical College, Bengbu, China. fyingyan@163.com
authors: Yingyan
authors: Y
authors: Fang
authors: Xiaolei
authors: X
authors: Guo
authors: Qin
authors: Q
authors: Gao
authors: Hongwei
authors: H
authors: Ye
authors: Sudong
authors: S
authors: Guan
mesh_terms: D000818:Animals; D001835:Body Weight; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D003964:Diaphragm / Q000378:metabolism / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism*; D013385:Succinate Dehydrogenase / Q000378:metabolism; D000099211:Phospholamban
chemical_list: D002118:Calcium; D002135:Calcium-Binding Proteins; D005947:Glucose; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013385:Succinate Dehydrogenase; D000099211:Phospholamban