Abstract:

Objective To investigate the impact of ginseng alcohol extract （GEE） on improving sleep quality in the aged Drosophila model by regulating the redox balance， and to elucidate its associated mechanism. Methods Thirty-two male drosophila melanogaster （7-days-old） were randomly selected as young group， while 64 male Drosophila melanogaster flies （35-days-old） were randomly assigned to aged model group （n=32） and GEE group （n=32）. The sleep parameters， including total sleep duration， daytime sleep duration， night sleep duration， 0-4 h of sleep duration after lights off （ZT0-4 sleep duration）， deep sleep duration， sleep episodetimes， sleep fragmentation， and the activity parameters such as the total number of locomotor activity daytime locomotor activity amount and nighttime locomotor activity amount were analyzed using the DAM2 Drosophila behavioral analysis system 7 d after administration. The grouping of the drosophila was as above， and there were 100 drosophila ineach group. The differentially expressed proteins in drosophila brain tissue were screened， identified， and functionally analyzed using two-dimensional fluorescence difference gel electrophoresis（2D-DIGE） and matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF/TOF-MS） proteomic methods. The grouping of the drosophila was as above， and there were 100 drosophila in each group.The activities of superoxide dismutase （SOD）， catalase （CAT）， and glutathione peroxidase （GSH-Px） and the levels of lipid peroxidation product （MDA） in brain tissue of the drosophila were determined using assay kits. Results Compared with young group， the total sleep duration daytime sleep duration and night sleep cluration of the drosophila in agaed group were decreased（P<0.05 or P<0.01）； and the sleep rhythm amplitude was shortened. Compared with aged group， the total sleep duration and daytime and nighttime sleep durations of the drosphila in GEE group were lengthened （P<0.01）. Compared with young group， the ZT0-4 sleep duration deep sleep duration and sleep fragment of the drosophila in aged group were decreased （P<0.05 or P<0.01）， and the sleep rhythm amplitude was shortened. Compared with young group， the ZT0-4 sleep duration， deep sleep duration， and single sleep fragment of the drosphila in GEE group were significantly prolonged （P<0.01）， and the sleep amplitude was increased.Compared with young group， there was no significant difference in diurnal spontaneous activity or total spontaneous activity of the drosophila in aged group（P>0.05）， while the nocturnal spontaneous activity was significantly increased （P<0.05）. Compared with aged group， the diurnal spontaneous activity， nocturnal spontaneous activity， and total spontaneous activity of the drosophila in GEE group were significantly decreased （P<0.05 or P<0.01）. A total of 47 differentially expressed proteins were selected in the 2D-DIGE electrophoretic mapping. Compared with young group， the expressions of 47 differentially expressed protein sites in aged group were down-regulated mainly including glutathione S-transferase， peroxiredoxin 1 and dihydrolipoic dehydrogenase， which were related to redox balance. Compared with young group， the activities of SOD， CAT and GSH-Px in brain tissue of the drosophila in aged group were decreased （P<0.05 or P<0.01）， and the level of MDA was increased （P<0.01）； compared with aged group， the activities of SOD， CAT and GSH-Px in brain tissue of the drosphila in GEE group were increased （P<0.05 or P<0.01）， and the MDA level was decreased （P<0.05）. Conclusion GEE has improvement effect on the sleep quality of aged drosophila， and its possible mechanism may be related to upregulating the activities of antioxidant enzymes， inhibiting the accumulation of lipid peroxidation products， and maintaining redox balance.

Key words: Ginseng, Aging, Sleep, Redox balance, Drosophila melanogaster, Proteome