Resveratrol Alleviates Oxidative Stress And Inflammation To Delay Senescence Of Retina In Nothobranchius Guentheri

Aging is a complex physiological process leading to organismal damage and even death.The retina is an important part of the visual system.Its unique physiological structure makes it extremely susceptible to oxidative stress and thus easy to aging.Retinal aging causes a variety of age-related ocular diseases and brings great inconvenience to people’s lives.Research on the protective effects of natural compounds on retina has become a major treatment strategy for preventing age-related ocular diseases.Resveratrol is a natural compound found in plants that has been shown to have a variety of pharmacological effects such as antioxidant,anti-aging,anti-inflammatory and anti-cancer.Previous research in our laboratory has shown that feeding resveratrol played a role in extending the lifespan of Nothobranchius guentheri.Nothobranchius — the annual teleost is becoming an emerging animal model for the study of aging in recent years because of its advantages of relatively short lifespan,rapid growth rate and artificial laboratory breeding.In this study,N.guentheri were used as research object.When fish grew to 4 months old(sexual maturity),they were randomly divided into control group and experimental group: the control group was fed with frozen nematode without added resveratrol,the experimental group was fed with frozen nematode added resveratrol(200 μg/g food).The fish were sacrificed when they reached the age required for the experiment.Experiments were conducted to investigate the effect of resveratrol on retinal aging and to detect the effect and mechanism of resveratrol on oxidative stress and inflammation related indicators during retinal senescence.The experimental results were as follows:1.To investigate the effects of resveratrol on retinal aging of the annual fish,we used HE staining,SA-β-gal staining and PCNA immunohistochemical to detect retinal tissues.The result of HE staining showed that the thickness of inner plexiform layer(IPL)and inner nuclear layer(INL)in 9-,12-month-old fish retina were significant lower than that in6-month-old fish,and resveratrol attenuated this reduction.Resveratrol inhibited the thinning of the retinal tissue structure;The result of SA-β-gal staining showed that SA-β-gal was mainly expressed in the retinal pigment epithelium(RPE),outer nuclear layer(ONL),inner core layer(INL)and ganglion cell layer(GCL).Resveratrol significantly reduced the activity of SA-β-gal in retina of the fish.SA-β-gal activity in the retina of 6-,9-month-old fish was rising compared with that in 3-month-old fish,and resveratrol significantly reduced SA-β-gal activity in the retina of 9-month-old fish.But there was no significant difference in6-month-old retina,which may be due to the short time of resveratrol feeding.The result of PCNA immunohistochemical staining showed that PCNA positive cells in the outer nuclear layer and ciliary marginal zone of retina were significantly reduced with aging.Resveratrol feeding increased PCNA positive cell number in the retina of 9-,12-month-old fish.The experimental results aboved indicated that resveratrol delayed the aging of retina in the annual fish.2.To investigate the effects of feeding resveratrol on retinal oxidative stress,immunohistochemical and qPCR were used for detection.The result of SIRT1 immunohistochemical staining showed that as the expression of SIRT1 protein decreased in the aged retina,resveratrol feeding significantly increased the expression of SIRT1 in the retina of 6-,9-,12-month-old fish.The result of qPCR showed that mRNA levels of Nrf2,PGC-1α and antioxidant enzymes glutathione peroxidase1(Gpx1),glutathione peroxidase2(Gpx2),catalase(CAT),Mn-superoxide dismutase(Mn-SOD),Cu Zn-superoxide dismutase(Cu Zn-SOD)were significantly reduced in retina of 9-month-old fish compared with that in6-month-old fish.Resveratrol treatment significantly increased their expression.3.To investigate the effect of resveratrol on retinal inflammation,qPCR and immunohistochemical were used for detection.The result of qPCR showed that the expression of GFAP and pro-inflammatory SASP factors IL-8,IL-1β,TNF-α in retina of 9-month-old fish were significantly increased compared with that in 6-month-old fish.Resveratrol treatment significantly decreased their expression.The result of NF-κB immunohistochemical staining showed that the expression levels of NF-κB protein in retina of 9-,12-month-old fish compared with that in 6-month-old fish were significantly increased,and resveratrol treatment significantly inhibited the expression of NF-κB protein.The above experimental results proved that resveratrol increased the expression of SIRT1,antioxidant regulators Nrf2,PGC-1α and downstream antioxidant enzymes,inhibited the expression of NF-κB and pro-inflammatory SASP factors.Accordingly,we speculated that resveratrol delayed the aging of retina in the annual fish with activation SIRT1 to mediate the antioxidant and anti-inflammatory signaling.