- 作者: Paik-Seong Lim a-c, Yi-Shing Ma a, Yueh-Mei Cheng c, Henry Chai c, Cheng-Feng Lee a, Tzu-Ling Chen a, Yau-Huei Wei a
- 作者服務機構: a Department of Biochemistry and Center for Cellular and MolecuIar Biology, National Yang-Ming University, Taipei, b Graduate Institute of Clinical Medicinal science, Chang Gung University , Taoyuan, c Department of Nephrology, Kuang Tien General Hospital, Taichung, Taiwan , Republic of China
- 中文摘要: --
- 英文摘要: Abundant evidence has been gathered to suggest thatmitochondrial DNA (mtDNA) sustains many more muta-tions and greater oxidative damage than does nuclearDNA in human tissues. Uremic patients are subject to astate of enhanced oxidative stress due to excess produc-tion of oxidants and a defective antioxidant defense sys-tem. This study was conducted to investigate mtDNAmutations and oxidative damage in skeletal muscle ofpatients with chronic uremia. Results showed that large-scale deletions between nucleotide position(np) 7,900and 16,300 of mtDNA occurred at a high frequency inmuscle of uremic patients. Among them, the 4,977-bydeletion (mtDNA ) was the most frequent and mostabundant large-scale mtDNA deletion in uremic skeletalmuscle. The proportion of mtDNA was found to cor-relate positively with the level of 8-hydroxy 2'-deoxygua-nosine (8-OHdG) in the total DNA of skeletalmuscle (r=0.62, p<0.05). Using long-range PCR and DNA sequenc-ing. we identified and characterized multiple deletions ofmtDNA in skeletal muscle of 16 of 19 uremic patientsexamined. The 8,041-by deletion, which occurred be-tween np 8035 and 16,075, was flanked by a 5-by directrepeat of 5'-CCCAT-3'. Some of the deletions were foundin more than 1 patient. On the other hand,we found thatthe mean 8-OHdG/10 dG ratio in the total cellular DNA ofmuscle of uremic patients was significantly higher thanthat of the controls (182.7±63.6 vs. 50.9±21.5, p=0.05). In addition, the mean 8-OHdG/10 dG ratio in mus-cle mtDNA of uremic patients was significantly higherthan that in nuclear DNA (344.0±56.9 vs. 146.3±95.8,p=0.001). Moreover, we found that the average contentof lipid peroxides in mitochondrial membranes of skele-tal muscle of uremic patients was significantly higherthan that of age-matched healthy subjects (23.76±6.06vs. 7.67±0.95 nmol/mg protein; p<0.05). The averagecontent of protein carbonyls in the mitochondrial mem-branes prepared from uremic skeletal muscles was sig-nificantly higher than that in normal controls (24.90±4.00 vs. 14.48±1.13 nmol/mg protein;p<0.05). Takentogether, these findings suggest that chronic uremialeads to mtDNA mutations together with enhanced oxi-dative damage to DNA, lipids, and proteins of mitochon-dria in skeletal muscle, which may contribute to theimpairment of mitochondrial bioenergetic function andto skeletal myopathy commonly seen in uremic pa-tients.
- 中文關鍵字: --
- 英文關鍵字: Uremia, Skeletal muscle, Mitochondris, DNA, Deletion, oxidative damage, Lipid peroxidation, Protein carbonyls