Effects Of Hops And Xanthohumol On Learning And Memory Impairment And Bone Loss Induced By Iron Overload

Objective:Iron overload is a risk factor for age-related memory impairment and bone loss.Our previous study found that Hop alcohol extract（HLE）and its active ingredient xanthohumol（XAN）can improve the learning and memory ability of aging mice through antioxidant effects,and have the potential to fight osteoporosis.Based on the above findings,this study used iron overload mouse aging model,high iron injury model of nerve cells and osteoblasts to investigate the improvement effect of HLE and XAN on iron overload induced learning and memory impairment and bone loss,and preliminarily explore the related mechanism,in order to provide the basis for the clinical application of hops in anti degenerative memory impairment and osteoporosis.Methods:（1）The model of memory impairment complicated with osteoporosis in iron overload mice was established by intraperitoneal injection of iron dextran（ID）.Y-maze and Morris water maze were used to investigate the effects of HLE and XAN on learning and memory,iron content and antioxidant enzyme activity in brain of mice.Western blot was used to investigate the effects of hle and xan on memory related proteins BDNF,ERK1/2,CREB,Akt/GSK3βand Nrf2 in hippocampus.At the same time,the effects of the two on bone morphometric parameters,serum bone metabolism indexes,bone related proteins and antioxidant enzyme activities of iron overload mice were investigated.（2）The effects of HLE and XAN on the proliferation,antioxidant enzyme activity,ROS level,Akt/GSK3βand Nrf2 signal of ID injured PC12 cells and osteoblasts were investigated.Results:（1）The protective effects of HLE and XAN on learning and memory impairment induced by iron overload in mice:HLE and XAN could increase the spontaneous exploration rate,shorten the swimming latency,promote the expression of BDNF,p-ERK and p-CREB in hippocampus of iron overload mice,effectively improve the learning and memory impairment of iron overload mice,improve SOD and GSH-PX avtivities in hippocampus of mice,reduce MDA1level,activate Akt signal and promote the expression of p-GSK3β,Nrf2,HO-1,NQO1 and SOD..（2）Effects of HLE and XAN on bone loss induced by iron overload in mice:HLE and XAN can improve bone tissue morphology and bone microstructure indexes,increase serum ALP and Ca²⁺levels of bone formation markers,up regulate the expression of COL-I and Runx2 in bone tissue,reduce serum TRAP-5b and CTX-I levels of bone resorption markers,inhibit the expression of NFATC1,MMP9,Cts K and c-Fos in bone tissue,and effectively improve bone metabolism Bone loss in iron overload mice.In addition,both of them can reduce the level of MDA in serum,increase SOD and GSH-PX activities,and up-regulate SOD expression in femur of mice.（3）Protective effect and mechanism of HLE and XAN on PC12 cells induced by iron overload:HLE and XAN can significantly increase the proliferation and SOD activity of ID injured PC12 cells,reduce the levels of LDH,MDA and ROS,activate Akt signal,and promote the expression of p-GSK3β,Nrf2,HO-1,NQO1 and SOD.（4）Protective effect and mechanism of HLE and XAN on osteoblast injury induced by iron overload:HLE and XAN can significantly promote the proliferation,ALP and SOD activities,reduce the levels of MDA and ROS,and promote the expression of p-Akt,p-GSK3β,Nrf2,HO-1,NQO1 and SOD of osteoblast injured by ID.Conclusion:HLE and XAN can effectively inhibit oxidative stress in brain and bone of iron-overloaded mice,improve learning and memory impairment and bone loss in mice,and may protect iron-damaged PC12 cells and osteoblast through Akt/GSK3βand Nrf2 pathways,which provides a new direction for the development of hops as novel anti-aging drugs for brain and bone diseases.