Effects of T-2 toxin on expression of fibroblast growth factor 8 and fibroblast growth factor receptor 3 in articular cartilage and bone marrow of rats under low selenium condition / 中华地方病学杂志

ABSTRACT

Objective:To study the effects of T-2 toxin on expression of fibroblast growth factor 8 (FGF8) and fibroblast growth factor receptor 3 (FGFR3) in articular cartilage and subchondral marrow of rats under low selenium condition, and to explore the mechanism of deep cartilage injury and secondary complications in Kaschin-Beck disease (KBD).Methods:Twenty-four healthy male SD rats weighted 60 - 80 g were selected, they were divided into conventional feed group (selenium content of 101.5 μg/kg) and low-selenium feed group (selenium content of 1.1 μg/kg) by random number table method, with 12 rats in each group. After 30 days of feeding, the conventional feed group was further divided into control group and T-2 toxin group (100 μg·kg -1·d -1), and the low-selenium feed group was further divided into low-selenium group and low-selenium+ T-2 toxin group, with 6 rats in each group. After 30 days of feeding, the rats were sacrificed and the knee cartilage with cancellous bone was taken. Pathological changes of knee cartilage were observed by HE staining. Immunohistochemical method was used to detect the expression of FGF8 and FGFR3 in cartilage and subchondral marrow of knee joint, positive expression rates of FGF8 and FGFR3 in articular cartilage were calculated, and the integrated optical density (IOD) values of FGF8 and FGFR3 positive expression in subchondral marrow were analyzed by Image-Pro Plus 6.0 software. Results:Under light microscope, chondrocytes in low-selenium+ T-2 toxin group were sparse, and empty chondrocytes in the deep and middle layers of articular cartilage increased, and chondrocytes died and became red cell shadows. The extracellular matrix dissolved and was slightly stained in deep region, turning into necrotic and unstructurized areas. Proliferating granulation tissue was visible nearby. The positive expression rate of FGF8 in articular cartilage of rats in low-selenium+ T-2 toxin group [(88.61 ± 10.97)%] was higher than that in control, low-selenium and T-2 toxin groups [(10.35 ± 2.48)%, (19.26 ± 3.08)%, (58.89 ± 9.29)%, P < 0.05]; IOD value of FGF8 positive expression in subchondral marrow [(16.73 ± 1.72) × 10 6] was higher than that in control, low-selenium and T-2 toxin groups [(1.20 ± 0.41) × 10 6, (4.33 ± 0.97) × 10 6, (12.80 ± 1.12) × 10 6, P < 0.05]. The positive expression rate of FGFR3 in articular cartilage of rats in low-selenium+ T-2 toxin group [(89.76 ± 8.59)%] was higher than that in control, low-selenium and T-2 toxin groups [(13.18 ± 2.25)%, (21.15 ± 2.33)%, (32.55 ± 6.72)%, P < 0.05]; IOD value of FGFR3 positive expression in subchondral marrow [(16.50 ± 5.36) × 10 6] was higher than that in control, low-selenium and T-2 toxin groups [(7.58 ± 1.02) × 10 6, (10.73 ± 7.13) × 10 6, (9.83 ± 5.63) × 10 6, P < 0.05]. Conclusion:Under low selenium condition, T-2 toxin changes expression of FGF8 and FGFR3 in deep chondrocytes of articular cartilage and subchondral marrow in rats, elevated expression of FGF8 and FGFR3 may be involved in the occurrence and development of secondary changes in KBD.