Abstract：
Kashin-Beck disease (KBD) is an endemic, environmentally associated cartilage disease. Previous studies have shown that the environmental suspected pathogenic factors of KBD, T-2 toxin and low selenium, are involved in the regulation of inflammation, oxidative stress and autophagy in some tissues and organs. In cartilage diseases, the level of cellular autophagy determines the fate of the chondrocytes. However, whether autophagy is involved in KBD cartilage lesions, and the role of low selenium and T-2 toxins in KBD cartilage injury and autophagy are still unclear. This work took the classical AMPK/mTOR/ULK1 autophagy regulatory pathway as the entry point to clarify the relationship between the environmental suspected pathogenic factors and chondrocyte autophagy. Transmission electron microscopy was used to observe the autophagy of chondrocytes in KBD patients. qRT-PCR and western blot were used to analyze the expression of AMPK/mTOR/ULK1 pathway and autophagy markers. The rat model of KBD was established by low selenium and T-2 toxin, the autophagy in rat cartilage was detected after 4- and 12-week interventions. Chondrocyte autophagy was found in KBD, and the AMPK/mTOR/ULK1 pathway was down-regulated. In the rat model, the pathway showed an up-regulated trend when low selenium and T-2 toxin, were treated for a short time or low concentration, and autophagy level increased. However, when low selenium and T-2 toxin were treated for a long time or at high concentrations, the pathway showed a down-regulated trend, and the autophagy level was reduced and even defective. In conclusion, in the process of KBD cartilage lesion, chondrocyte autophagy level may increase in the early stage, and decrease in the late stage with the progression of lesion. Low selenium and T-2 toxins may affect autophagy by AMPK/mTOR/ULK1 pathway.
摘要：
大骨节病（KBD）是一种地方病，环境相关的软骨疾病。以前的研究表明，KBD的环境可疑致病因素，T-2毒素和低硒，参与炎症的调节，一些组织和器官的氧化应激和自噬。在软骨疾病中，细胞自噬水平决定了软骨细胞的命运。然而,自噬是否参与KBD软骨损伤，低硒和T-2毒素在KBD软骨损伤和自噬中的作用尚不清楚。本研究以经典的AMPK/mTOR/ULK1自噬调控通路为切入点,阐明环境可疑致病因子与软骨细胞自噬的关系。透射电镜观察KBD患者软骨细胞的自噬。qRT-PCR和westernblot分析AMPK/mTOR/ULK1通路和自噬标志物的表达。用低硒和T-2毒素建立大鼠KBD模型,在4周和12周的干预后检测到大鼠软骨中的自噬。软骨细胞自噬在KBD中发现，AMPK/mTOR/ULK1通路下调。在大鼠模型中,低硒和T-2毒素时，该途径呈上调趋势，短时间或低浓度处理，自噬水平增加。然而,当低硒和T-2毒素长时间或高浓度处理时，该途径呈下调趋势，自噬水平降低甚至有缺陷。总之,在KBD软骨损伤的过程中，软骨细胞自噬水平在早期可能升高,并随着病变的进展在晚期减少。低硒和T-2毒素可能通过AMPK/mTOR/ULK1通路影响自噬。
