ABSTRACT
Objective To investigate the role of SIRT1/PGC-1α pathway in the auditory cortex aging of guinea pigs with age-related hearing loss and whether the electroacupuncture can delay aging process of the auditory cortex in the aged guinea pigs induced by D-galactose through the regulation of SIRT1/PGC-1α pathway.Methods Thirty 4-month-old guinea pigs were randomly divided into three groups including the control group (n=10),D-galactose group (model group,n =10),and D-galactose and electroacupuncture group (electroacupuncture group,n =10).The elderly group (n=10) was composed of 18-month-old guinea pigs.The guinea pigs in model group and electroacupuncture group had been subcutaneously injected with D-galactose(300 mg· kg-1· d-1)for 6 weeks.Moreover,the guinea pigs in electroacupuncture group electroacupunctured at Tinggong and Yifeng for 15 minutes half an hour later once a day.After 6 weeks,the ABR threshold of guinea pigs in each group was detected.The mRNA and protein expression of SIR1 and PG-C-1α in auditory cortex of guinea pigs were detected by real -time fluoreacence quantitative PCR and Western Blot.Results There was a significant increase in the ABR threshold of the model group and elderly group (P＜0.001,compared with the control group),decrease in the electroacupuncture group (P＜0.001,compared with the model group),and no significant difference between model group and elderly group(P＞0.05).There was significant decrease in the expression of SIRT1 and PGC-1α in the model groupand elderly group(P＜0.05,compared with the control group),and significant increase at mRNA and protein levels in the electroacupuncture group (P＜0.05,compared with the model group).Conclusion SIRT1/PG-C-1α pathway may play a role in aging process of the auditory cortex in the aged guinea pigs induced by D-galactose,and electroacupuncture at Tinggong and Yifeng may increase the antioxidant capacity of auditory cortex by activating SIRT1/PGC 1α in guinea pigs with age-related hearing loss,thus delaying the aging process of auditory cortex.
ABSTRACT
Objective To investigate the effects and mechanisms of electroacupuncture at Tinggong and Yifeng on the local expression of insulin like growth factor-1 (IGF-1) and glucose metabolism in the auditory cor‐tex of guinea pig .Methods Eighteen Adult pigmented guinea pigs were randomly divided into 3 groups .Guinea pigs in electroacupuncture at auricular points group (EAPG ,n= 7) were electroacupunctured at Tinggong and Yifeng acupoints simultaneously for 15 minutes every day ,and electroacupunctur lasted 7 days .The electroacupuncture at non acupoint group (ENAG ,n=6) was electroacupunctured at non acupoints for the same time .The control group (CG ,n=5) received no treatment .After anesthetized ,guinea pigs were injected 18 F-FDG via dorsocuboidal vein , and scanned by PET/CT .PET image and CT image were processed and reconstructed in the workstation to observe the uptake of imaging agent in the brain of guinea pigs .The maximum SUV values and its ratios between auditory cortex and cerebellum were measured .The expression of IGF-1 mRNA were detected by real-time fluorescence quantitative PCR .The results were analyzed by the one-way ANOVA and P<0 .05 means statistical significance . Results 1 .Changes in glucose energy metabolism in the auditory cortex .The ratios of the maximum SUV value betweenthe auditory cortex and cerebellum were 0 .75 ± 0 .06 ,0 .84 ± 0 .05 and 0 .71 ± 0 .06 for CG ,EAPG and ENAG re‐spectively .There was a significant difference between the CG and EAPG (P=0 .042) ,the EAPG and ENAG (P=0 .009) ,and no significant difference between the CG and ENAG (P=0 .361) .2 .The fold changes in IGF-1 mR‐NA were 1 .34 ± 0 .24 ,2 .03 ± 0 .36 and 0 .92 ± 0 .23 for CG ,EAPG and ENAG respectively .There was a significant increase in IGF-1 mRNA expression in auditory cortex of the EAPG (P=0 .002 ,compared with the CG) ,and a significant difference between the EAPG and ENAG groups (P<0 .001) .Conclusion 1 .Acupuncturing at Tinggong and Yifeng point can improve glucose metabolism in the auditory cortex of guinea pig . 2 . Acupuncturing at Tinggong and Yifeng point can result in increase of the local expression of IGF-1 in the auditory cortex of guinea pig .