Mitochondrial apoptosis of lymphocyte is induced in type 2 diabetes.
BACKGROUND
Lymphocyte function and homeostasis is associated with immune defence to infection. Apoptosis of lymphocytes might be a considerably important component which has an impact on immunity to infections in people with hyperglycemia. The aim of this study was to explore the mitochondrial apoptosis pathway of lymphocyte in diabetic patients.


METHODS
Sixty patients with type 2 diabetes mellitus and fifty healthy volunteers were included in this study. Annexin V and propidiumiodide (PI) were joined in the isolated lymphocytes and the rate of lymphocyte apoptosis was calculated with flow cytometry. Observation of the lymphocytes was done using transmission electron microscopy; mitochondria had been extracted and then mitochondrial membrane potential (MMP) was detected to assess mitochondrial function; the mRNA level of Bcl-2, cytochrome c (Cyt-C), caspase-9 and caspase-3 were analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
Apoptosis rate of lymphocyte was significantly higher in diabetic group than that in normal control group (P < 0.05). Transmission electron microscopy showed lymphocyte shrinkage and breakage, chromatin condensation and less mitochondria; a fall in MMP levels was also evident; Bcl-2 concentration was reduced and the expressions of caspase-9, caspase-3 and Cyt-C were elevated (P < 0.05) in diabetic patients.


CONCLUSIONS
The rate of lymphocyte apoptosis was significantly higher in type 2 diabetic patients than that in normal population. Mitochondrial apoptosis pathway may play a very important role in decreasing function of lymphocyte in diabetes.
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Hui
H
Xu
Department of Urology, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Yanbo
Y
Chen
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Yanxiang
Y
Li
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Fangzhen
F
Xia
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Bing
B
Han
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Huixin
H
Zhang
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Hualing
H
Zhai
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Hui
H
Wu
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
Ying
Y
Li
Endocrinology and Metabolism Research Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China. Email: luyingli2008@126.com.
Yingli
Y
Lu
D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology; D053148:Caspase 3 / Q000235:genetics; D053453:Caspase 9 / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D051028:bcl-2-Associated X Protein / Q000235:genetics
D051028:bcl-2-Associated X Protein; D053148:Caspase 3; D053453:Caspase 9