Objective To investigate the death of chondrocytes in rats which feed with T-2 toxin under selenium (Se) deficient conditions.Methods Thirty two healthy male SD rats were divided into two groups by weight which were normal diet group and Se deficiency diet group,16 rats in each group.Rats in normal diet group were fed with Se 101.5 μg/kg diet,and rats in Se deficiency diet group were fed with Se 1.1 μg/kg diet for 30 d.Normal diet group was divided into control group and T-2 toxin group,and Se deliciency diet group was randomly divided into Se-deficiency group and Se-deficiency plus T-2 toxin group,8 rats in each group.After that,rats in T-2 toxin and Se-deficiency plus T-2 toxin groups were administrated intragastrically with T-2 toxin (100 μg/kg) everyday for 30 d.Rats were put to death,the left knee was taken and stained with hematoxylin-eosin and SafraninFast green,pathological changes of rat's knee joint cartilage were observed under light microscopy,expression levels of active caspase-3 and receptor interacting protein 3 (RIP3) in rat's articular cartilage cells were determined via the immunohistochemical method.The apoptosis was also detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL).Results Red ghost outlines of chondrocyte and multiple chondral cell clusters surrounded the non-cell areas in deep zone of articular cartilage of knee joint stained with hematoxylineosin were seen in Se-deficiency plus T-2 toxin group under light microscope.In the superficial zone of cartilage,the positive percent of TUNEL and active caspase-3 in Se-deficiency plus T-2 toxin group was higher than those of control group,Se-deficiency group and T-2 toxin group [(7.47-± 0.34)％ vs (4.68 ± 0.54)％,(2.67-± 0.64)％,(2.56 ±0.54)％;(4.75 ± 0.67)％ vs (1.24 ± 0.25)％,(0.00 ± 0.00)％,(0.00 ± 0.00)％,P ＜ 0.05].In the middle zone of cartilage,the positive percent of TUNEL,active caspase-3 and RIP3 in Se-deficiency plus T-2 toxin group was significantly higher than those of control group,T-2 toxin group and Se-deficiency group [(72.06 ± 6.15)％ vs (16.10 ± 3.00)％,(19.57 ± 3.49)％,(19.33 ± 5.19)％;(51.13 ± 4.18)％ vs (10.97-± 3.01)％,(15.36 ± 4.37)％,(15.23 ± 3.13)％;(25.91 ± 13.39)％ vs (1.59 ± 1.14)％,(4.32 ± 2.91)％,(7.50 ± 5.00)％,P ＜ 0.05].The positive percents of TUNEL,active caspase-3 and RIP3 were not significantly different in the deep zone (P ＞ 0.05).Conclusion The death of the middle zone in the rat cartilage induced by T-2 toxin under selenium deficient conditions isapoptosis and necroptosis.

ObjectiveTo resolve the problems related to the abnormal interpretations of real-time fluorescence polymerase chain reaction （PCR） results for tri-allele， to formulate the interpretation methods of real-time fluorescence PCR by referring to multiplex PCR fragment analysis， so as to obtain an accurate， simple and cheap detection method for ABCB1 tri-allele. MethodsA total of 2 794 DNA samples were collected from Xi'an Mental Health Center from March 2020 to March 2021， and 5% of which were selected as experiments. Real-time fluorescence PCR method and multiplex PCR fragment analysis method were performed respectively. According to the comparison of Ct values of PCR curves and the comparison of base peak intensity in multiplex PCR fragment analysis， comparison and analysis were conducted on the interpretation results of the two methods， and samples with different interpretation results were verified， thereafter， PCR interpretation method was formulated. ResultsA total of 139 samples were collected， of which 120 alleles and 19 tri-allele were detected. The results of allele detection by two methods were absolutely consistent. In combination with the results of multiplex PCR fragment analysis， a method for the interpretation of real-time fluorescence PCR for 19 cases of tri-allele was developed as follows： when ∣∣Ct._G－Ct._T∣－∣Ct._G－Ct._A∣∣ in amplification curve was less than 3， the interpretation results were the combination of the base pairs with small Ct values； when ∣∣Ct._G－Ct._T∣－∣Ct._G－Ct._A∣∣ was greater than or equal to 3， the interpretation results were homozygotes from the base pairs with minimum Ct values. According to the interpretation method， the results of real-time fluorescence PCR were revised， and it showed 1 case of G/G， 1 case of A/A， 4 cases of T/G， 5 cases of T/A and 8 cases of T/T， which were consistent with the results of multiplex PCR fragment analysis. ConclusionReferring to the multiplex PCR fragment analysis method， the interpretation of ABCB1 tri-allele by real-time fluorescence PCR is developed， and the two interpretation methods are in good agreement.