Protective effects of regular exercise and Korea red ginseng against high-fat diet-increased renal injury in ᴅ-galactose-induced aging rats
노화 유발 쥐에서 고지방식이가 신장손상에 미치는 영향과 운동 및 홍삼에 의한 신장손상 개선효능 연구
- 주제(키워드) Age-related renal injury , ᴅ-Galactose , Exercise , High-fat diet , Korean red ginseng , Oxidative stress
- 발행기관 아주대학교
- 지도교수 이수환, 정이숙
- 발행년도 2014
- 학위수여년월 2014. 2
- 학위명 박사
- 학과 및 전공 일반대학원 의학과
- 실제URI http://www.dcollection.net/handler/ajou/000000016277
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
A decline in renal function is seen commonly in aging. Aging further increase oxidative stress in the kidney and are associated with reduced renal function. Aging is progressive accumulation of oxidative agents. Advanced glycation end products (AGEs) and advanced lipoxidation end products (ALEs) formation has been implicated in the aging process. Obesity induced by a high-fat diet (HFD) may reduce renal function. However, the impact of obese on the age-related renal disease is not well understood. Exercise reduces oxidative stress. Korean red ginseng (KRG) has been reported to ameliorate oxidative tissue injury and has an anti-aging effect. The purpose of this study was to investigate whether HFD would accelerate ᴅ-galactose (GAL)-induced renal injury and to examine the preventive effects of a regular exercise and KRG on GAL/HFD -induced renal injury. In the first experiment, age-related renal injury was induced by an administration with GAL (100 mg/kg, i.p.) in the absence or presence of high-fat diet (60% kcal as fat) for 9 weeks. The exercise group was trained on a motorized treadmill for 60 min/day, 5 times/week over the same period. In the second experiment, in vitro inhibitory effect of KRG on AGEs-cross-linking was examined by enzyme-linked immunosorbent assay (ELISA), and KRG (200 mg/kg/day) was given to GAL plus HFD-induced aging rats for 9 weeks. Immunohistochemical staining for 8-OHdG (a specific marker of oxidative DNA damage) and CMLs (a marker of both glycation and lipoxidation reactions) revealed that GAL-treated rats fed a HFD showed aggravated renal injury associated with more pronounced renal AGEs/ALEs formation and oxidative DNA damage. In TUNEL assay, the numbers of TUNEL-positive cell in the GAL/HFD group were significantly higher than the GAL group. The expression of activated caspase-3 protein and Bax/Bcl-2 ratio also were significantly increased in the GAL/HFD group than that in the GAL group. Moreover, imuunohistochemical staining for synaptopodin and WT-1, well-known podocyte markers, revealed that HFD aggravates the loss of podocytes in renal glomeruli. However, the regular exercise restored all these renal changes in HFD plus GAL-treated rats. KRG inhibited AGEs and collagen cross-link at ten-fold less concentration (IC50=55.65 μg/ml) than aminoguanidine (IC50=563.54 μg/ml), a well-known glycation inhibitor. When rats were fed with a HFD for 9 weeks in GAL-induced aging rats, renal AGEs accumulation, extracellular high mobility group box 1 protein (HMGB1), a signal of tissue damage) and receptor for AGE (RAGE) were extensively expressed in renal tissues of the GAL/HFD group than that in the GAL group. HMGB1 was clearly translocated from the nucleus to the cytoplasm in renal tubular epithelial cells. However, treatment of HFD plus GAL-induced aging rats with KRG restored all these renal changes. In summary, when rats were fed with a HFD for 9 weeks in GAL-induced aging rats, oxidative DNA damage, protein glycations, renal cell apoptosis and cytoplasmic translocation of HMGB1 were caused in renal glomerular cells and tubular epithelial cells. However, the regular exercise and KRG treatment restored all these renal changes in GAL/HFD-treated rats. Therefore, this study suggested that long-term HFD may accelerate the deposition of AGEs/ALEs and oxidative renal injury in GAL-treated rats. This HFD-increased renal injury in GAL-induced aging rats could be suppressed by regular exercise and KRG through the repression of oxidative injury.
more목차
I. INTRODUCTION 1
A. Age-related oxidative renal injury 1
B. AGEs and oxidative stress 2
C. High mobility group box protein-1 and receptor for AGE 3
D. Role of podocyte in glomerular pathobiology 3
E. Exercise and renal injury 4
F. Korean red ginseng and renal injury 5
G. Obesity-related renal injury 6
H. Aims of study 6
II. MATERIALS AND METHODS 8
A. KRG preparation 8
B. Animals and experimental design 8
C. Analysis of metabolic data 9
D. In vitro assay of the cross-linking of glycated proteins 10
E. Immunohistochemical staining 10
F. Double staining for TUNEL and Wilms tumor antigen-1 11
G. Apoptosis analysis 11
H. Statistical analysis 12
III. Results 13
A. Body weight and blood lipid profile 13
B. CML accumulation in renal tissues 16
C. Oxidative DNA damage in renal tissues 18
D. Apoptosis assay in renal tissues 20
E. Expression of Bax and Bcl-2 in renal tissues 22
F. Caspase-3 activation 25
G. Glomerular podocyte loss 27
H. Inhibitory effect of KRG on glycated proteins cross-linking in vitro. 31
I. Body weight and blood lipid profile 33
J. Oxidative DNA damage in renal tissues 36
K. Protein glycations in renal tissues 38
L. Apoptosis assay in renal tissues 40
M. HMGB1 cytoplasmic translocalization in renal tissues 42
N. RAGE Expression in renal tissues 44
IV. DISCUSSION 47
V. CONCLUSION 53
VI. REFERENCES 54
국문요약 67
