Resveratrol Inhibits Endoplasmic Reticulum Stress Through SIRT1/NRF2 To Delay Aging Of Ovary In Nothobranchius Guentheri

Aging is a complex process in which the structure and function of various tissues,organs and systems gradually decline with age.Aging cells secrete senescence associated secretory phenotypes(SASP),including inflammatory cytokines,growth factors and chemokines.The increased expression of SASP related factors will increase the pressure of cell synthesis and transport proteins,resulting in the accumulation of unfolded proteins,and then induce endoplasmic reticulum stress(ERS)to help degrade the misfolded proteins in cells.When ERS is excessive,it will affect cell survival,proliferation and differentiation,even drives the aging process.As an important reproductive organ,the aging of ovary will cause endocrine disorders,affect the reproductive ability of females and induce related diseases.ERS may play a promoting role in cell aging and individual aging.The average lifespan of Nothobranchius guentheri used in this paper is 12 months.During the natural aging process,behavioral,histological and biochemical levels show corresponding changes.This kind of annual bony fish shows the characteristics of short life cycle,fast reproduction speed and easy feeding in laboratory,and is a good biological model for anti-aging research.Resveratrol is a kind of natural product,which is extracted from the secondary metabolite of Polygonum cuspidatum,grape and other plants.It has many biological functions such as anti-aging,anti-inflammatory and anti-tumor.Resveratrol is an activator of SIRT1,which activates the nuclear transcription factor NRF2 by deacetylation,thereby inhibiting the expression of NF-κB and regulating the inflammatory response in organisms.Here,130 female N.guentheri were randomly divided into two groups: control group and resveratrol treated group when fish grew to 4 months old.The control group was fed with standard food and the experimental group was fed with resveratrol-supplemented food(200 μg/g).When the fish were 6-,9-and12-month-old,they were killed on ice and their ovaries were taken to detect the changes of aging related indexes and the effect of resveratrol during the aging process of ovaries.Then select 6-,9-month-old fish to detect the effect of resveratrol on ovarian aging related proteins.Results are as follows:1.The activity of SA-β-gal and the accumulation of lipofuscin increased with aging in ovaries of the fish,and resveratrol decreased both of them significantly after treatment.2.HE staining and immunohistochemistry were used to analyze the changes in the number of follicles at different stages of development and the ability of ovarian cells to proliferate in 6-,9-and 12-month-old fish.It was found that the number of follicles in primary growth stage,cortical vesicle stage and vitellogenesis stage decreased with age,the number of follicles in oogonium stage and atretic stage increased significantly,and the PCNA positive staining intensity decreased significantly.Resveratrol treatment significantly increased the number of follicles in vitellogenesis stage,decreased the number of follicles in oogonium stage and atretic stage,and increased the PCNA positive staining of cells in the ovary.3.Immunohistochemistry and qPCR were used to detect the expression of SIRT1 and NRF2 in ovaries of the 6-,9-month-old fish.It was found that the expression level of both decreased with age,and increased significantly after resveratrol feeding.qPCR detected that the expression levels of inflammatory-related factor NF-κB,IL-1β,TNF-α and IL-8 were up-regulated with age,and resveratrol significantly decreased them.4.The expression of endoplasmic reticulum stress markers in ovary was detected by qPCR and immunohistochemistry.The results showed that the expression levels of GRP78 and CHOP in 9-month-old fish were significantly higher than that in6-month-old fish.Resveratrol significantly reversed the up-regulation of GRP78 and CHOP with the increase of age.Long-term feeding of resveratrol reduced the age-related markers SA-β-gal and lipofuscin,improved ovarian reserve function and the proliferation ability of ovarian cells,and down-regulated endoplasmic reticulum stress in the ovary.Based on the above results,we hypothesized that resveratrol inhibited NF-κB by activating SIRT1/NRF2 signaling pathway,thereby inhibiting the expression of SASP-related pro-inflammatory cytokine IL-1β,TNF-α,IL-8,and resisting the development of ERS,thus delaying aging of ovaries in the annual fish.