Effect of treadmill exercise on apoptosis in the retinas of streptozotocin-induced diabetic rats

트레드밀 운동이 streptozotocin에 의해 유발된 당뇨 쥐의 망막 신경세포 사멸에 미치는 영향

  • Received : 2012.05.30
  • Accepted : 2012.07.05
  • Published : 2012.08.31

Abstract

In the present study, we investigated the effect of treadmill exercise on apoptotic neuronal cell death in the retinas of streptozotocin-induced diabetic rats. Twenty-eight male Sprague-Dawley rats were used for this study. The animals were divided into four groups(n = 7 in each group):(1) control group, (2) exercise group, (3) diabetes-induced group, (4) diabetes-induced and exercise group. Diabetes mellitus(DM) was induced by intraperitoneal injection of streptozotocin. The rats in the exercise groups were forced to run on the treadmill for 30 minutes once a day, five times per a week, during 12 weeks. In this study, a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay and western blot for the expressions of caspase-3, cytochrome c, Bax, and Bcl-2 in the retinas were conducted for the detection of apoptotic retinal cell death. The present results showed that the number of TUNEL-positive cells was increased in the retinas of the diabetic rats, whereas treadmill exercise suppressed this number. The expressions of pro-apoptotic factors caspase-3, cytochrome c, and Bax were enhanced and the expressions of anti-apoptotic factor Bcl-2 was decreased in the retinas of the diabetic rats. In contrast, treadmill exercise suppressed the expressions of caspase-3, cytochrome c, and Bax and increased the expression of Bcl-2. The present study demonstrated that treadmill exercise suppressed diabetes-induced apoptotic neuronal cell death in the retinas. Based on the present results, treadmill exercise may be effective therapeutic strategy for the alleviating complications of diabetes patients.

본 연구는 당뇨를 유발한 흰쥐에서 트레드밀 운동이 망막 신경세포의 사멸에 억제 효과가 있는지를 실험 하였다. 본 연구에서 Sprague-Dawley계 흰쥐 28마리를 대조군, 운동군, 당뇨군, 당뇨운동군으로 분류하여 각 군당 7마리씩 배정하였다. 당뇨는 streptozotocin을 복강에 주사하여 유발하였다. 운동군은 분당 8 m의 속도로 하루 30분씩 주 5회, 총 12주 동안 트레드밀 운동을 실시하였다. 본 연구의 결과, 당뇨 유발 흰쥐의 망막에서 세포사멸 인자인 terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL)-양성 세포수 그리고 caspase-3, cytochrome c, Bax의 발현이 증가되었으며, 항 세포사멸 인자인 Bcl-2의 발현은 감소되었다. 트레드밀 운동은 TUNEL-양성 세포수 그리고 caspase-3, cytochrome c, Bax의 발현을 감소시켰으며, Bcl-2의 발현은 증가시켰다. 본 실험의 결과, 당뇨에 의한 망막의 세포사멸 증가에 트레드밀 운동이 억제 작용을 나타내었으며, 따라서 트레드밀 운동은 당뇨 환자들에서 후유증을 경감시키는데 효과적인 치료법임을 알 수 있었다.

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Acknowledgement

이 논문은 2011년도 정부(교육과학기술부)의 재원으로 한국연구재단의 지원을 받아 연구되었음. (NRF-2011-332-G00091)