Objective In order to investigate the relationship between erythrocyte immune function and seleni- um(Se) level. Method Red blood cell immune adherence(RCIA) function,serum RCIA regulatory factor, blood Se content and activities of glutathione peroxidase(GPX) of residents in Keshan disease(KD) endemic and non-endemic areas were comparatively studied. Forty-eight residents in KD endemic area aged 13～ 16 years were divided into 2 groups. The residents in the experimental group were orally given 200μg Se daily as Se yeast for 12 weeks, and their erythrocyte Se content and activity of glutathione peroxidase (GPX),RCIA function,serum RCIA regulatory function and circulating immune complexes(CIC) content were determined. ResultsThe results showed that the rosette for- mation rates of erythrocyte and blood Se levels of the residents in KD area were significantly lower and the rosette formation inhibitory rate of serum RCIA of the residents in KD area was significantly higher than those in the non-endemic area. Erythrocyte Se contents, GPX activities and rosette formation rates of erythrocyte were sig- nificantly increased and the rosette formation inhibitory rates of serum RICA were significantly decreased after sup- plementing Se,but the difference in the contents of serum CIC was not significant. ConclusionThe increase of ery- throcyte immune function by Se-supplement might be one of the effective mechanisms in the prevention of KD by Se- supplement.

Objective To investigate the expressions of matrix metalloproteinases(MMPs) in Kashin-Beck disease(KBD) cartilage as well as in a KBD rat model of T-2 toxin poisoning under selenium deficient conditions, and to investigate the effect of T-2 toxin on MMP-13 expression in human chondrocytes in vitro in order to determine a possible mechanism underlying KBD. Methods Samples of articular cartilage were divided into 2 groups:controls(samples from 5 normal children, traffic accident or operation), and KBD(samples from 5 children with KBD, auctopsy). Thirty-two Sprague-Dawley rats were divided into two groups by body weight using random number table: normal diet group(n = 16) and selenium-deficient diet group(n=16). The selenium level in normal diet was 101.500μg/kg, and in selenium-deficient diet was 1.118μg/kg. Rats were fed for 4 weeks with selenium-deficient or normal diet, respectively. After successful build up of the low selenium rat model, normal diet group was then subdivided into 2 sub-groups: normal group(n = 8) and normal diet plus low T-2 toxin group(n = 8);and selenium-deficient diet group was also subdivided into 2 sub-groups: selenium-deficient group ( n = 8 ) and selenium-deficient diet plus T-2 toxin group ( n = 8 ) . T-2 toxin of 100 μg·kg-1·d-1 was administered by intragastric administration for 30 days. Then the rats were sacrificed, and their knee joints were processed for histopathological evaluation. MMP-1 and MMP-13 locations in cartilages were performed by inmmunohistochemistry. Human chondrocytes C28/I2 were cultured in vitro. The experiment was divided into 4 groups: empty vector plasmid group, MMP-13 promoter plasmid group, MMP-13 promoter plasmid plus 20 μg/L T-2 toxin group and MMP-13 promoter plasmid plus 40 μg/L T-2 toxin group. MMP-13-luciferase reporter plasmid and vector plasmid were transiently transfected into C28/I2 cells for 24 hours, and then treated with 20 - 40 μg/L T-2 toxin for 24 hours. Transactivation of human MMP-13 promoter was analyzed using luciferase reporter constructs containing sequences spanning-1602 to+20 bp in C28/I2 chondrocytes. Results The percentages of chondrocytes staining for MMP-1 in the superficial and middle zones of KBD samples [(29.73 ± 10.12)%, (28.27 ± 0.91)%] were significantly higher than those of controls[(2.47 ± 0.11)%, (0.00 ± 0.00)%, all P < 0.05]. The percentages of chondrocytes staining for MMP-13 in the superficial and middle zones of KBD samples [(13.21 ± 4.32)%, (41.85 ± 6.32)%] were significantly higher than those of controls[(5.72 ± 0.31)%, (0.00 ± 0.00)%, all P<0.05]. The percentages of chondrocytes staining for MMP-13 in the superficial and middle zones of rats fed with selenium-deficient diet plus T-2 toxin group[(13.21 ± 4.32)%, (61.85 ± 8.68)%] were significantly higher than those of the normal and selenium-deficient groups[(2.43 ± 0.22)%, (5.89 ± 0.69)%, (3.03 ± 0.29)%, (25.99 ± 0.57)%, all P < 0.05]. Moreover, T-2 toxin activated the MMP-13 promoter detected with luciferase reporter assays in C28/I2 cells. The luciferase activities in MMP-13 promoter plasmid plus 20 μg/L T-2 toxin group and MMP-13 promoter plasmid plus 40μg/L T-2 toxin group(0.082 78 ± 0.008 40, 0.103 35 ± 0.013 19) were significantly higher than those in empty vector plasmid group and MMP-13 promoter plasmid group(0.024 19 ± 0.000 96, 0.040 32 ± 0.003 56, all P < 0.05). Conclusions These data suggest that T-2 toxin induces cartilage matrix degradation through up-regulation of MMP-13 promoter expression. Increased MMPs staining intensity in KBD cartilage and the rat KBD model of T-2 toxin poisoning under selenium deficient conditions suggest that matrix degradation appear to be driven by MMPs activity.

Objective To investigate the expressions of interleukin-1β(IL-1β), interleukin-6(IL-6) and tumor necrosis factor alpha(TNF-α) in cartilage of children with Kashin-Beck disease(KBD) in order to provide a possible mechanism of the disease. Methods Articular cartilage tissues of 5 KBD children(KBD group) were selected from KBD children autopsy samples keeping in Institute of Endemic Diseases, Medical School of Xi’an Jiaotong University; articular cartilage tissues of 5 normal children ( control group ) were selected from non-KBD areas of Shaanxi Province, three cases were from accident death children, two cases were the samples of congential malformation of six finger. Expressions of IL-1β, IL-6 and TNF-α in the cartilage were detected using immunohistochemistry; the cells of articular cartilage were divided into three areas (superficial zone, middle zone and deep zone) to analyze the expressions of IL-1β, IL-6 and TNF-α. Results The expressions of IL-1β in superficial zone , middle zone and deep zone of articular cartilage of KBD group (63.50 ± 7.19, 54.75 ± 5.50, 66.20 ± 9.91) were significantly higher than those of control group(5.75 ± 1.26, 0.00 ± 0.00, 0.00 ± 0.00, all P<0.05). The expression of IL-6 in superficial zone of articular cartilage in KBD group(55.25 ± 6.24) was significantly higher than that of control group(0.00 ± 0.00, P<0.05). The expressions of TNF-αin all zone of articular cartilage of KBD group(33.25 ± 6.50, 3.75 ± 0.96, 29.80 ± 1.92) were significantly higher than those of control group (3.74 ± 0.82, 0.00 ± 0.00, 0.00 ± 0.00, all P < 0.05). Conclusion The levels of IL-1β, IL-6 and TNF-α are up-regulated in articular cartilage of KBD children, suggesting that cytokines may play an important role in matrix degradation in KBD children cartilage.