Immunohistochemical Studies Of TRAIL And Caspase-3 In Hashimoto's Hyroiditis

Objective: To investigate the expression and significance of TNF-related apoptosis- inducing ligand(TRAIL) and caspase-3 in thyroid follicular epithelial cell in the pathogenesis and pathological changes of Hashimoto's Thyroiditis(HT).Methods: Expressions and distributions of TRAIL and caspase-3 in thyroid tissues from 26 patients with HT and 12 normal cases were investigated with S-P immunohistochemical method.Results:1) High characteristic expressions of TRAIL and caspase-3 in thyroid follicular epithelial cell from HT were observed. Strongly positive immunostained thyroid follicular epithelial cells of TRAIL were mainly distributed in follicles adjacent to lymphocytic infiltrates. Staining of infiltrating lymphocytes for TRAIL was found to be negative while caspase-3 was weakly positive.2) Positive rates of TRAIL in specimens of HT was significantly higher than that in normal thyroid tissue(72.92% vs 41.67%;P=0.040). The expression of TRAIL in specimens of HT increased significantly compared with that in controls(0.051±0.016 vs 0.016±0.010;P<0.05)。3) Positive rates of caspase-3 in specimens of HT was significantly higher than that in normal thyroid tissue(92.31% vs 33.33%;P=0.003). The expression of caspase-3 in specimens of HT increased significantly compared with that in controls(0.065±0.025 vs 0.022±0.008;P<0.05)。4) In HT,TRAIL was positively correlated to caspase-3(rs=0.631,P=0.001). Conclusion: Both TRAIL and caspase-3 may contribute to the pathogenesis and pathological changes of HT. Expressions of TRAIL in thyroid follicular epithelial cell with HT may induce the apoptosis and the destruction of follicular cell, which may primarily mediated by activating caspase-3.