Objective To investigate the effect of endoplasmic reticulum stress on sensitivity of glioma cell line U87 to temozolomide (TMZ) and underlying mechanism.Methods (1) Glioma U87 cells were routinely cultured for 24 h in vitro;different concentrations of TMZ (0,12.5,25,50,100 μmol/L) were added to intervene the cell proliferation of U87 cells for 24 h;MTT method was used to detect the cellular proliferation inhibition rate,and half maximal inhibitory concentration (IC50) of TMZ was calculated;tunicamycin (TM) treatment (0,2,4,8 μmol/L) was given to the cells for 6 h,and then,50 μmol/L TMZ was given for 24 h,and cellular proliferation inhibition rate of U87 was detect by MTT method.(2) U87 cells were randomly divided into control group,TM group,TMZ group and TM+TMZ group;pretreatment of TM for 6 h was given to cells from TM group and TM+TMZ group;and 50 μmol/L TMZ was given to cells from TMZ group and TM+TMZ group;same amount of medium was given to cells from control group;24 h after treatment,the apoptotic rate was examined by flow cytometry;Westem blotting was used to detect the protein expressions of caspase-3,B-cell lymphoma 2 associated X protein (Bax),O-6-methlguanine-DNA methyltransferase (MGMT),glucose-regulated protein 78 (GRP78),and inositol-requiring enzyme 1 (IRE-l).Results (1) MTT showed that IC50 of TMZ was 50 μmol/L.As compared with that of 0 μmol/L TM+50 μmol/L TMZ group or 2 μmol/L TM+50 μmol/L TMZ group,the cellular proliferation inhibition rate of 4 μmol/L TM+50 μmol/L TMZ group and 8 μmol/L TM+50 μmol/L TMZ group was significantly decreased (P＜0.05).(2) As compared with TMZ group,TM+TMZ group had significantly decreased apoptotic rate (46.98％±4.79％ vs.35.74％ ±4.09％),significantly decreased caspase-3 and Bax protein expressions,and significantly increased MGMT,GRP78 and IRE-1 protein expressions (P＜0.05).Conclusion Endoplasmic reticulum stress can increase the resistance gene MGMT expression,decrease the chemotherapy sensitivity to TMZ,and induce chemoresistance ofglioma cell line U87.

BACKGROUND:Kidney deficiency is the main pathogenesis of osteoporosis.To study the relationship between the two major syndrome types of kidney deficiency,Kidney-Yang deficiency and Kidney-Yin deficiency,is beneficial for the development of clinical diagnosis and treatments based on the combination of disease and syndrome. OBJECTIVE:To evaluate the biomechanical differences of the rat femurs with Kidney-Yang deficiency and Kidney-Yin deficiency caused by Yougui pills,and to demonstrate the scientific efficacy of medication based on the combination of disease and syndrome in osteoporosis from a biomechanical perspective. METHODS:The bilateral ovaries of 60 female Sprague-Dawley rats were surgically removed to establish an ovariectomized osteoporosis model.At 10 weeks after modeling,all the rats were randomly divided into a Kidney-Yang deficiency group(n=30)and a Kidney-Yin deficiency group(n=30).Rats with Kidney-Yang deficiency were given gluteal intramuscular injection of hydrocortisone,while rats with Kidney-Yin deficiency were orally administered with thyroid tablet suspension,once a day,for 14 consecutive days.After successful modeling,20 rats in each group were given a suspension of Yougui pills by gavage once a day for 12 consecutive weeks and the remaining 10 rats were used as the control group without intervention.After gavage,the microstructural parameters of the bone were measured using Micro-CT scanning.Three-point bending,finite element simulation,femoral head compression,and surface indentation distribution experiments of the femurs were performed on a mechanical testing machine. RESULTS AND CONCLUSION:Micro-CT revealed that the femoral bone density,bone volume fraction,bone surface density,trabecular number,and trabecular separation were improved in the Kidney-Yin deficiency+Yougui pills group compared with the Kidney-Yin deficiency group(P＜0.05);the femoral bone volume fraction,bone surface density,trabecular number,and trabecular thickness were improved in the Kidney-Yang deficiency+Yougui pills group compared with the Kidney-Yang deficiency group(P＜0.05).The three-point bending experiment showed that the femur elastic modulus,maximum bending strength and bending fracture strength were decreased(P＜0.05)and toughness was increased(P＜0.05)in the Kidney-Yang deficiency+Yougui pills group compared with the Kidney-Yang deficiency group.Finite element simulation showed that Yougui pills could significantly improve the bending resistance of the femurs in the Kidney-Yang deficiency group,but had no significant effect on the Kidney-Yin deficiency group.The femoral head compression experiments showed that Yougui pills could enhance the ability of the femoral head to resist deformation in the Kidney-Yang deficiency group,but there was no significant difference in the effect of Yougui pills on the surface properties of the femoral head in the Kidney-Yin deficiency group and the Kidney-Yang deficiency group.To conclude,Yougui pills can significantly enhance the biomechanical properties of the osteoporotic bones with Kidney-Yang deficiency,but have no significant effect on the osteoporotic bone with Kidney-Yin deficiency.