ABSTRACT
OBJECTIVE To study the protective effects of mangiferin against oxidative stress injury of myocardial cells induced by hydrogen peroxide （H2O2）， and its effects on the expression of nuclear factor of activated T cell cytoplasmic 4（NFATc4）. METHODS H9c2 myocardial cells were cultured in vitro and divided into blank group， H2O2 group， and 50， 100， 150 μmol/L mangiferin groups. Mangiferin groups were treated with different concentrations of mangiferin for 12 h， and then were subjected to H2O2 （200 μmol/L） stimulation for 12 hours together with the H2O2 group； relative survival rate was detected in each group， and the levels of superoxide dismutase （SOD）， catalase （CAT） and malondialdehyde （MDA） in cell supernatant and reactive oxygen species （ROS） in H9c2 cells were measured. Meanwhile， the expressions of apoptosis-related proteins [B cell lymphoma 2 （Bcl- 2）， Bcl-2 associated X protein （Bax）， cleaved caspase-3] and nuclear protein NFATc4 were determined. Furthermore， the NFATc4 interference sequence was transfected， and the effects of NFATc4 on oxidant stress indexes and apoptosis-related proteins in H2O2- induced myocardial cells were investigated. RESULTS Compared with blank group， relative cell viability， the levels of SOD and CAT， relative expression of Bcl-2 were decreased significantly， while the levels of MDA and ROS， relative expressions of Bax， cleaved caspase-3 and nuclear protein NFATc4 were increased significantly （P＜0.05 or P＜0.01）. Compared with the H2O2 group， the above indexes of 100 and 150 μmol/L mangiferin groups were reversed significantly （P＜0.05）. After the transfection of the NFATc4 interference sequence， the expression of nuclear protein NFATc4 was down-regulated significantly； the levels of MDA and SOD， the protein expressions of Bax and cleaved caspase-3 were all decreased/down-regulated significantly， while the levels of SOD and CAT， and the protein expression of Bcl-2 were all increased/up-regulated significantly， compared with H2O2 group （P＜ 0.05）. CONCLUSIONS Mangiferin can relieve H2O2-induced oxidative stress of H9c2 cells， reduce the apoptosis and inhibit the nuclear translocation of NFATc4， thereby alleviating myocardial cell damage； reducing the nuclear level of NFATc4 protein is related to reducing H2O2-induced oxidative stress and cell apoptosis.
ABSTRACT
Objective:To observe the effects of T-2 toxin on expression of hepatocyte growth factor (HGF) and HGF receptor (C-Met) in articular cartilage and epiphyseal cartilage of rats under low selenium condition.Methods:Twenty-four healthy male SD rats weighted 60-80 g were randomly divided into conventional diet group (selenium content of 101.5 μg/kg) and low-selenium diet group (selenium content of 1.1 μg/kg), with 12 rats in each group. After 30 days of feeding, the conventional diet group was further divided into conventional group and T-2 toxin group (100 μg·kg -1·d -1), and the low-selenium diet group was further divided into low-selenium group and low-selenium+T-2 toxin group (100 μg·kg -1·d -1), with 6 rats in each group. After 30 days of feeding, the rats were sacrificed and the cartilage of knee joint was taken, the morphological changes of knee articular cartilage and epiphyseal cartilage were observed by HE staining under light microscope. Immunohistochemical method was used to detect the expression of HGF and C-Met in knee articular cartilage and epiphyseal cartilage, and positive expression rates of HGF and C-Met were calculated. Results:Under light microscope, chondrocytes of articular cartilage and epiphyseal cartilage in low-selenium+T-2 toxin group were sparse, and the necrosis and structural area were found in the deep layer, and the extracellular matrix of chondrocytes in the region was degraded and light stained, and proliferating granulation tissue was visible nearby. The positive expression rates of HGF in articular cartilage [(21.97 ± 6.90)%, (49.41 ± 8.24)%, (76.39 ± 5.88)%] and epiphyseal cartilage [(23.36 ± 12.49)%, (58.43 ± 14.48)%, (66.59 ± 10.83)%] of rats in low-selenium, T-2 toxin and low-selenium+T-2 toxin groups were higher than those in conventional group [(9.13 ± 6.01)%, (11.14 ± 4.67)%, P < 0.05]. The positive expression rates of C-Met in articular cartilage [(25.34 ± 7.53)%, (58.21 ± 12.54)%, (81.46 ± 7.89)%] and epiphyseal cartilage [(35.21 ± 4.71)%, (40.84 ± 2.03)%, (49.41 ± 6.29)%] of rats in low-selenium, T-2 toxin and low-selenium+T-2 toxin groups were higher than those in conventional group [(11.21 ± 5.11)%, (12.12 ± 4.71)%, P < 0.05]. Conclusion:T-2 toxin may affect the expression of HGF and C-Met in articular cartilage and epiphyseal cartilage of rats under low selenium condition.
ABSTRACT
Objective To observe the expression level of insulin-like growth factor-1 receptor (IGF-1R) in the cartilage tissue of children with Kaschin-Beck disease (KBD) and T-2 toxin-poisoned rats under low selenium condition,and the effect of IGF-1R inhibitor on apoptosis of human normal chondrocytes (C28/I2 cells),and to investigate the role of IGF-1R in the pathogenesis of KBD.Methods The knuckles of dead children (5 cases) in the KBD areas,car accident death and congenital 6 finger deformity operation children (5 cases) in non-KBD areas in Shaanxi were collected,the expression of IGF-1R in the articular cartilage was detected by immunohistochemistry.Thirty-two male Sprague-Dawley rats with a body mass of 60-80 g were selected,according to the body mass,they were divided into the routine feed group (selenium content:101.5 μg/kg) and the low-selenium feed group (selenium content:1.1 μg/kg) by random number table method,16 rats in each group.After 30 days of feeding,the routine feed group was divided into control group and T-2 toxin group (100 ng·kg-1·d-1),the low-selenium feed group was divided into low selenium group and low selenium + T-2 toxin group,8 rats in each group,the expression of IGF-1R in the articular cartilage of the left knee joint was detected by immunohistochemistry after 30 days of feeding.C28/I2 cells were cultured in vitro and treated with T-2 toxin 0 (control),6,12,and 24 μg/L,and each concentration of T-2 toxin was accompanied with sodium selenite (+ 0.1 mg/L) for 72 h.Meanwhile,IGF-1R inhibitor with 0 (control),250,500,and 1 000 μg/L was treated on C28/I2 cells for 48 h.The expression levels of IGF-1R mRNA and protein in chondrocytes were detected by Real-time PCR and Western blotting,and the apoptosis of chondrocytes was detected by flow cytometry.Results Compared with the control group [(100.00 ± 0.00)％,(100.00 ± 0.00)％],the expression rates of IGF-1R positive cells in articular cartilage surface and middle layers [(72.71 ± 4.75)％,(36.33 ± 4.32)％] of children in KBD group were significantly reduced (t =12.852,32.650,P ＜ 0.01).Compared with control group [(100.00 ± 0.00)％,(100.00 ± 0.00)％,(100.00 ± 0.00)％],the expression rates of IGF-1R positive cells in articular cartilage middle layer [(20.83 ± 2.69)％,(26.45 ± 2.84)％,(20.34 ± 1.82)％],deep layer [(33.55 ± 5.66)％,(48.89 ± 8.39)％,(25.51 ± 7.50)％],and the expression rates of IGF-1R positive cells [(47.50 ± 1.47)％,(28.66 ± 3.58)％,(40.52 ± 6.78)％] in the hypertrophic layer of the metaphyseal plate of rats in low selenium,T-2 toxin,and low selenium + T-2 toxin groups were significantly reduced (P ＜ 0.01).C28/I2 cells were cultured in vitro,compared with the control group,IGF-1R mRNA and protein expression levels in each T-2 toxin groups were significantly reduced (P ＜ 0.05).The expression levels of IGF-1R mRNA (1.95 ± 0.35,2.44 ± 0.17,2.40 ± 0.15) in 6,12,24 μg/L T-2 toxin + 0.1 mg/L selenium groups were significantly higher than those in T-2 toxin groups (0.80 ± 0.08,0.63 ± 0.08,0.61 ± 0.11,t =-12.259,-11.279,-13.371,P＜ 0.05).The expression levels of IGF-1R protein (1.67 ± 0.70,1.07 ± 0.26) in 6,12 μg/L T-2 toxin + 0.1 mg/L selenium groups were significantly higher than those in T-2 toxin groups (0.52 ± 0.05,0.72 ± 0.05,t =-25.977,-10.776,P ＜ 0.05).Compared with the control group [(5.33 ± 0.85)％,(4.03 ± 1.15)％],C28/I2 cells early apoptosis rates [(8.26 ± 1.51)％,(13.00 ± 0.72)％,(13.19 ± 1.05)％] in each of IGF-1R inhibitor groups,and late apoptosis rates [(8.50 ± 0.71)％,(14.21 ± 1.10)％] in 500,1 000 μg/L IGF-1R inhibitor groups were increased significantly (P ＜ 0.05).Conclusions The expressions of IGF-1R in the cartilage tissue of KBD children and T-2 toxin-poisoned rats under low selenium condition are decreased.T-2 toxin decreases the expression of IGF-1R in chondrocytes,and selenium can partly inhibit the effect of T-2 toxin on IGF-1R.Down-regulation of IGF-1R causes chondrocyte apoptosis,and it may play an important role in KBD chondrocyte apoptosis.
ABSTRACT
Aim To investigate the effect of sphingo-sine kinase 1 (SphK1 )on unilateral ureteral obstruc-tion(UUO)-induced tubulointerstitial fibrosis and ex-plore the possible mechanism.Methods The CD-1 mice were randomly divided into four groups:sham-op-eration group(Sham),PF-543 treatment control group (Sham +PF-543),model group(UUO)and PF-543 treatment group(UUO +PF-543).On 1 ,3,7 and 1 4 d after operation,eight mice were selected randomly from each group and sacrificed.The protein expressions of SphK1 ,mature TGF-β1 ,FN,ColⅠ,LC3,Beclin1 ,Atg5 and Atg1 2 were observed by Western blot.The histo-logical changes were examined by Masson′s trichrome stain.Immunhistochemistry was performed to measure the levels of expression of SphK1 ,FN and Col Ⅰ. Transmission electron microscope was used to observe the autophagic body.Results SphK1 expression and autophagy were both upregulated in a mouse model of kidney fibrosis induced by UUO. Meanwhile, in-creased mature TGF-β1 and deposition of extracellular matrix(ECM)were observed in tubulointerstitial areas compared with sham-operated mice.After intraperito-neal injection with the SphK1 specific inhibitor PF-543 in UUO mice,enhanced expression of SphK1 and acti-vated autophagy were significantly abrogated.Howev-er,aggravation of renal fibrosis was detected when SphK1 inhibitor PF-543 was applied to suppress SphK1 expression in UUO mice.Conclusion SphK1 activa-tion is renoprotective through the induction of autoph-agy in the pathogenesis of kidney fibrosis.
ABSTRACT
Objective To investigate the significantly elevated incidence of hepatitis C and mortality of cirrhosis and hepatocellular carcinoma (HCC) in Jianping county, and to explore the epidemiological features. Methods The data from database of death registry and infectious disease surveillance in Jianping county, Liaoning Province were analyzed. The distributions of incidence of hepatitis B and hepatitis C, mortality of cirrhosis and HCC in 23 villages and towns were investigated.Spearman's correlation was used to explore the correlations between hepatitis, cirrhosis and HCC.Results The standardized mortality of HCC in males and females in Jianping county were 77. 6/10~5and 22. 0/10~5, respectively, which were 2. 0 and 1. 7 times, respectively of the average levels of Liaoning rural areas. The incidence of hepatitis C was 58. 0/10~5 , which was 9. 5 times of the averagelevel of Liaoning Province. There were positive correlations between incidence of hepatitis C and mortality of cirrhosis (r=0. 495, P = 0. 008), and mortality of cirrhosis and HCC (r=0. 646, P<0.01). Conclusions The incidence of hepatitis C and mortality of cirrhosis and HCC in Jianping county are significantly higher than the average levels of Liaoning Province. Further investigations of the suspected causes are needed.
ABSTRACT
Objective To assess the association between air pollution and daily mortality of circulatory system diseases.Methods All death records of the deceased who lived in urban area of Shenyang and died from circulatory system disease during Jan 1,1992 to Dec 31,2000 were collected.We used the semi-parametric generalized additive model to study the relationship between short-term daily average temperature and daily mortality of circulatory system diseases after controlling the confounding factors of long-term trends,humidity,air pressure,work days and season,etc.Results The optimal temperature for all people was 23.4℃.And it was 23.6℃ for male and 23.2℃ for female.A significant graphically 'V' shape relationship between mortality caused by circulatory diseases and ambient temperature was found.The relationship between the temperature changes and the mortality caused by cardiovascular diseases was significant,but not significant with cerebrovascular diseases.The mortality caused by cardiovascular diseases increased 0.0275/100 000 while the temperature increasing each 1℃ above 23.4℃,and increased 0.0062/100 000 while temperature decreasing each 1℃ below 23.4℃.People over 65 years old were the most sensitive population for temperature changing,their mortality caused by cardiovascular diseases increased 1.1909/100 000 when the temperature increasing each 1℃ from 26.6℃.But people under 65 years old were not sensitive to temperature changing,their mortality caused by cardiovascular diseases was all less than 0.0011/100 000 no matter the temperature was higher or lower 1℃ from the optimal temperature.There was no significant difference of the effect of temperature changing on mortality caused by cardiovascular between male and female.Conclusion The "V" shape relationship between mortality caused by cardiovascular diseases and ambient temperature clues us on that temperature left from the optimal temperature could increase the death rate caused by cardiovascular diseases and temperature closed to the optimal temperature could decrease the death rate caused by cardiovascular diseases.