THE EXPERIMENTAL STUDY ON THE EFFECTS OF SIX MYCOTOXINS ON THE CULTURAL CHONDROCYTES

The effects of deoxynlvalenol (DON), T--2 toxin, nivalenol (NIv), hutenolide (BuT).alternariol methyl ether(AME) and monlliformin (cON ) on rabbit articular chondrocytes were observed by using the method of chondrocyte monolayer culture. The amounts or DNA in chondrocytesand glucuronate in matrix were measured. And the chondrocytes were observed by inversion microscope and transmission electron microscope (TEM). The results showed that the cultured chondrocytes were damaged by all the six mycotoxinsl and the synthesis of DNA and the divided reproductionof chondrocytes were restrained; the damage errect was more evident, esl,ecially in the early stage ofculturel the higher concentration or toxin in the media was used, the lower density of the culturalckondrocytes was observed; the cells were even round damaged and dead, so long as the media contolued toxin. When the six mycotoxins arrected the cultural chondrocytes r.spectively, three dirfereut kinds or ultrastructural changes in ckondrocytes were seen by TEa. The relationship betweenmycotoxiu and KBD was preliminarily discussed, and some problems still need further investigation..

Promotion of the articular cartilage proteoglycan degradation by T-2 toxin and selenium protective effect

Objective: To identify the relationship between T-2 toxin and Kashin-Beck disease (KBD),the effects of T-2 toxin on aggrecan metabolism in human chondrocytes and cartilage were investigated in vitro. Methods: Chondrocytes were isolated from human articular cartilage and cultured in vitro. Hyaluronic acid (HA),soluble CD44 (sCD44),IL-1β and TNF-α levels in super-natants were measured by enzyme-linked immunosorbent assay (ELISA). CD44 content in chondrocyte membrane was deter-mined by flow cytometry (FCM). CD44,hyaluronic acid synthetase-2 (HAS-2) and aggrecanases mRNA levels in chondrocytes were determined using reverse transcription polymerase chain reaction (RT-PCR). Immunocytochemical method was used to investigate expressions of BC-13,3-B-3(-) and 2-B-6 epitopes in the cartilage reconstructed in vitro. Results: T-2 toxin inhibited CD44,HAS-2,and aggrecan mRNA expressions,but promoted aggrecanase-2 mRNA expression. Meanwhile,CD44 expression was found to be the lowest in the chondrocytes cultured with T-2 toxin and the highest in control plus selenium group. In addition,ELISA results indicated that there were higher sCD44,IL-1β and TNF-α levels in T-2 toxin group. Similarly,higher HA levels were also observed in T-2 toxin group using radioimmunoprecipitation assay (RIPA). Furthermore,using monoclonal antibodies BC-13,3-B-3 and 2-B-6,strong positive immunostaining was found in the reconstructed cartilage cultured with T-2 toxin,whereas no positive staining or very weak staining was observed in the cartilage cultured without T-2 toxin. Selenium could partly inhibit the effects of T-2 toxin above. Conclusion: T-2 toxin could inhibit aggrecan synthesis,promote aggrecanases and pro-inflammatory cytokines production,and consequently induce aggrecan degradation in chondrocytes. These will perturb metabolism balance between aggrecan synthesis and degradation in cartilage,inducing aggrecan loss in the end,which may be the initiation of the cartilage degradation.

T-2毒素致软骨细胞损伤临界值和硒保护实验研究

目的：主要探索Ｔ－２毒素对体外培养软骨细胞致损临界值以及硒保护作用。方法：应用单层培养传代软骨细胞，用生化方法检测软骨细胞ＤＮＡ量和蛋白量，透射电子显微镜观察软骨细胞超微结构。结果：（１）Ｔ－２毒素在０．００１～０．００５ｍｇ／Ｌ培养液中（以下相同）剂量范围内，随浓度增加，Ｔ－２毒素对软骨细胞ＤＮＡ合成和细胞分裂增殖影响逐渐增大，加硒后该影响有所减弱，但仍不能阻止损伤的发生；（２）Ｔ－２毒素在０．０００５ｍｇ／Ｌ时，对软骨细胞的影响甚微；Ｔ－２毒素在０．００１ｍｇ／Ｌ和０．００５ｍｇ／Ｌ时，细胞损伤明显，与对照组比较有显著差别（Ｐ＜０．００１）。

T－2毒素对培养软骨细胞生长代谢的作用

报告了Ｔ－２毒素对培养软骨细胞生长代谢的作用。结果显示，在软骨细胞生长早期和旺盛时期，Ｔ－２毒素抑制细胞ＤＮＡ合成，影响软骨细胞的分裂增殖，同时也影响到细胞的代谢功能，其毒性作用随Ｔ－２浓度升高细胞损伤加重。对于较成熟的软骨细胞，其毒性作用不明显。