[Transmission disequilibrium test for 15 short tandem repeat loci in Kashin-Beck disease and their interaction with low selenium].

OBJECTIVE: To identify the genetic susceptibility to Kashin-Beck disease (KBD) and explore the interaction between low selenium (Se) and the susceptibility gene loci in KBD. METHODS: The DNA samples collected from 23 KBD nuclear families were analyzed using PCR and GeneScan Analysis 3.7 and Genotyper3.7 software. The haplotype relative risk (HRR) and transmission disequilibrium test (TDT) were used to test the data of the genotypes. The serum selenium (Se) concentration was measured by atomic fluorescence spectrometry, and the interaction between low Se and the susceptibility loci was calculated using a binary logistic regression. RESULTS: In the 23 nuclear families, the alleles of D2S151 (248 bp), D2S305 (320 bp), and D11S4094 (194 bp) showed significant correlation to KBD (P<0.05). Serum Se concentrations in the studied individuals was 0.037 µg/ml. No significant statistical interaction was observed between low Se exposure and the susceptibility loci (P>0.05). CONCLUSION: The polymorphisms in the STR loci D2S305, D2S151, and D11S4094 or the polymorphism loci near them might been related to KBD susceptibility. Low Se exposure shows no significant interaction with the susceptibility loci.

[Effects of selenium and/or iodine deficiency on chondrocyte apoptosis in rats].

OBJECTIVE: To explore the effects of selenium and/or iodine deficiency on chondrocyte apoptosis in articular cartilage in rats. METHODS: Forty-eight Sprague-Dawley rats were randomly divided into selenium deficiency group, iodine deficiency group, combined selenium and iodine deficiency group, and control group. Chondrocyte apoptosis was detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) method, and Bcl-2 and Bax in articular cartilage were stained by immunohistochemistry in F3 generation of rats. RESULTS: In articular cartilage, the positive rate of apoptotic chondrocytes stained by TUNEL in the upper and middle zones in selenium deficiency group, iodine deficiency group, and combined selenium and iodine deficiency group (all P < 0.05) were significantly higher than that in control group. The apoptotic chondrocytes were prominent in the middle zone. The positive percentage of chondrocytes apoptosis was not significantly different among these three groups (P > 0.05). Compared with the control group, the expressions of both Bcl-2 and Bax were significantly higher in the upper and middle zone in the selenium deficiency group, iodine deficiency group, and combined selenium and iodine deficiency group (all P < 0.05); however, the expressions of Bcl-2 and Bax were not significantly different among these three groups (P > 0.05). CONCLUSION: Selenium and/or iodine deficiency may induce chondrocyte apoptosis.

[Familial aggregation and sibling heritability in Kashin-Beck disease].

OBJECTIVE: To explore the family aggregation and the role of hereditary factors in the pathogenesis of Kashin-Beck disease (KBD). METHODS: With a stratified sampling method, the general population of 14 villages of Linyou County were studied, from whom 225 KBD probands were selected using systematic sampling at the rate of (1/2). A total of 304 siblings of the probands were ascertained, and in these sibling pairs, the segregation ratio, heritability in different age groups and weighted mean heritability of the siblings were estimated using the methods of Li-Mantel-Grart and Falconer. RESULTS: The KBD distribution scope in the KBD families exceeded the scope of binomial distribution (P<0.001), suggesting obvious family aggregation. The prevalence rate in the siblings of the KBD pedigree was 19.41% (59/304), significantly higher than that in the 14 KBD villages [10.90% (1180/10823), chi2=21.62, P<0.001]. The segregation ratio and heritability in the siblings of the KBD pedigrees were 0.061 and 28.61%, respectively. CONCLUSION: As a polygenetic inheritance disease, KBD exhibits obvious familial aggregation, and genetic susceptibility accounts for (1/4) of the risk factors for KBD.

[Butenolide induces apoptosis of cultured chondrocytes: study of its mechanism].

OBJECTIVE: To observe cell apoptosis and Bcl-2 and Bax expression changes of chondrocytes induced by butenolide (BUT) and the inhibitory effect of selenium against BUT-induced chondrcyte apoptosis, to gain insights into the mechanism by which BUT induces chondrcyte apoptosis. METHODS: Cartilage tissue reestablished from human fetal articular chondrocytes in vitro were treated with BUT at the concentrations of 0.1, 1.0 and 5.0 microg/ml and with the protective factor selenium. TUNEL method was used to detect chondrocyte apoptosis, which was quantified by flow cytometry. Immunohitochemistry was performed to analyze the expression of Bcl-2 and Bax in the reestablished cartilage tissue. RESULTS: BUT exposure induced chondrocyte apoptosis, and the apoptosis rate increased with the concentration increment of BUT from 0 to 1.0 mg/ml, resulting also increased positive expression rate of Bcl-2 and Bax(P<0.05). The apoptosis rate of chondrocytes in BUT+ selenium group was significantly lower than that of BUT groups (P<0.05), as was the positivity rate of Bcl-2 and Bax expression (P<0.05). CONCLUSION: BUT induces chondrocyte apoptosis in positive relation with BUT concentration (from 0 to 1.0 mg/ml) and causes increased expressions of Bcl-2 and Bax. Selenium can inhibit the chondrocyte apoptosis induced by BUT.