AIM:To study the expression of glucose transporters(GLUTs)and silent information regulators(SIRTs/sirtuins)in the liver of diabetic rats and human hepatocytes(LO2 cells)treated with high glucose.METHODS:(1)Twenty male SD rats were randomly divided into normal control(NC)group and diabetes mellitus(DM)group.The rats in DM group were given single intraperitoneal injection of streptozotocin(STZ,60 mg/kg)to establish the DM model,while the rats in NC group were intraperitoneally injected with equal volume of solvent once.Fasting blood glucose(FBG)and body mass were measured every 2 weeks.After 12 weeks of rearing,the blood and liver tissues of the rats were ob-tained after anesthesia with 1%sodium pentobarbitone,the biochemical indicators of blood were detected,and the liver in-dex was calculated.Hematoxylin-eosin(HE)staining and periodic acid-Schiff(PAS)staining were used to observe liver histopathological changes.Lipid accumulation in liver tissues was detected by oil red O staining.The expression levels of GLUTs and SIRTs family member proteins were detected in rat liver tissues.(2)The LO2 cells were treated with different concentrations of glucose for 48 h.The viability of the cells in each group was measured by CCK-8 assay,and Western blot was used to detected the protein expression levels of GLUTs and SIRTs in the cells.RESULTS:(1)Compared with NC group,the rats in DM group were depressed,lost weight,and the FBG and liver index were significantly increased(P＜0.05).The results of HE staining showed that the hepatic sinuses were dilatated and congested near the central vein in DM rats,and mild edema and scattered infiltration of inflammatory cells were found in liver cells.The results of oil red O staining showed the red fat droplets were diffusely scattered within liver cells in DM group.The results of PAS staining showed that there were numerous diffuse light purple circular droplets in the cytoplasm of the liver cells in the central ve-nous area of the DM rats.Western blot showed that the protein levels of GLUTs were higher and the protein levels of SIRTs were lower than those in NC group(P＜0.01).(2)The results of CCK-8 assay showed that the viability of LO2 cells was increased in 50 mmol/L glucose group(P＜0.01),without significant difference in 75,100 and 125 mmol/L glucose groups(all P＞0.05),and decreased in 150,175 and 200 mmol/L glucose groups(all P＜0.01).Later,150 mmol/L glu-cose was used as the high-glucose intervention condition.Western blot showed that the protein levels of GLUTs and SIRTs in LO2 cells under high glucose intervention were consistented with the results in animal experiments.CONCLUSION:High concentration of glucose can cause liver damage in SD rats and reduce the viability of human hepatocytes(LO2 cells).It can also increase the expression of GLUTs and decrease the expression of SIRTs in rat liver tissues and LO2 cells.Therefore,GLUTs and SIRTs family members may be the target proteins of diabetes-induced liver injury.

BACKGROUND:Exercise training can improve osteoporosis,but its effects and mechanisms on senile osteoporosis are not fully understood. OBJECTIVE:To observe the effect of treadmill exercise on osteoporosis and wnt/β-catenin signal pathway in aged rats. METHODS:Sixteen 24-month-old male Sprague-Dawley rats were randomly divided into osteoporosis group(n=8)and treadmill group(n=8)and eight 6-month-old male Sprague-Dawley rats were used as young control group.The model of senile osteoporosis was replicated by natural aging and the rats in the treadmill group were treated with treadmill exercise once a day,5 days a week,for 8 weeks.Levels of bone metabolic markers such as type I collagen cross-linked C-terminal peptide,tartrate resistant acid phosphatase,osteocalcin and bone specific alkaline phosphatase were detected by ELISA;bone mineral density of the left femur and L5 was measured by dual energy X-ray;bone scanning and bone microstructure quantitative analysis were performed by bone micro-CT;and the mRNA and protein expression levels of wnt3a,β-catenin,LRP5,DKK1 and GSK3β were detected by RT-PCR and western blot,respectively. RESULTS AND CONCLUSION:Compared with the young control group,the osteoporosis group showed a reduction in serum bone specific alkaline phosphatase and osteocalcin levels(P<0.05),bone mineral density of the femur and L5,the number of tibia and L4 bone trabeculae,bone volume,bone volume fraction(P<0.05),and mRNA and protein expression of wnt3a,β-catenin,and LRP5 in bone marrow tissue(P<0.05)as well as an increase in serum levels of tartrate resistant acid phosphatase and type I collagen cross-linked C-terminal peptide(P<0.05),the intertrabecular space between the tibia and L4,structural model index(P<0.05),and mRNA and protein expression of DKK1 and GSK3 β in bone marrow tissue(P<0.05).In addition to the reduced number of trabeculae in the tibia and L4 vertebrae,the trabeculae were structurally disturbed and sparsely aligned and fractured.Compared with the osteoporosis group,the treadmill group showed an increase in serum bone specific alkaline phosphatase and osteocalcin levels(P<0.05),bone mineral density of the femur and L5(P<0.05),the number of tibial trabeculae,bone volume,bone volume fraction(P<0.05),mRNA and protein expression of wnt3a,β-catenin,and LRP5 in bone marrow tissue(P<0.05)but a reduction in the serum levels of tartrate resistant acid phosphatase and type I collagen cross-linked C-terminal peptide,L4 trabecular space,tibial trabecular space,structural model index,and mRNA and protein expression of DKK1 and GSK3 β in bone marrow tissue(P<0.05).In addition to the increased number of tibial and L4 trabeculae,the trabeculae were arranged in a regular and dense pattern and were connected to a network.To conclude,treadmill exercise may improve osteoporosis in aged rats by activating the wnt/β-catenin signal pathway.