The Study On Ralationship Between Apoptosis And Proliferation In Hashimoto's Thyroiditis

INTRODUCTION: Hashimoto's thyroiditis (HT) is a typical organ-specific autoimmune disease, characterized by diffuse lymphocytic infiltration of the thyroid and subsequent thyroid follicle atrophy and destruction. In recent years, it has been reported that apoptosis plays an important role in the pathogenesis of this disease, but the proliferative characteristic, the relationship between apoptosis and proliferation is still unknown. AIM: To observe apoptotic level as well as expression and distribution of relationship between PCNA and Fas, FasL, Bcl-2 or Bax in HT, and to investigate the characteristic of apoptosis and proliferation. Methods: Specimen from nontoxic goiter(NTG, n=16) were used as control. Apoptosis level was detected with TU7NEL, and expression and distribution of PCNA, Fas ,FasL, BCL-2 and Bax in thyroid tissues from 16 patients with HT were investigated by immunohistochemical double staining method. Results: The TUNEL positive ratio,also called apoptotic index(AJ),was 0.9?.64% and 33.92?4.69% in NTG and HT respectively, while the PCNA positive ratio or proliferation index(PI) was 4.23.36% and 8.45.61%, and AI/PI ratio in NTG and HT was 0.48 .86,4.52+2.37 respectively. It indicates that all of Al , P1 , AIJPI ratio in LIT were significantly higher than that from NTG(p<0.000 1). The rate of positive immunostaining and intensity of immunostaining for Fas,FasL,Bcl-2,and Bax proteins from HT were both significantly higher than that from NTG(p<0.05). All of them assumed characteristic distribution and expression.And the co-expression of both PCNA and Fas, FasL, Bcl-2 or Bax on part of thyrocytes was observed, whose rates of positive cells correspondingly were 14.46%, 29.13%, 32.72%, 15.93%. Conclusion: Both apoptotic and proliferative activity in HT increase, especially in apoptotic level.There is the phenomenon of co-expression of PCNA with FAS,FasL,Bcl-2 or Bax on part of thyrocytes in UT. It indicates that the imbalance between apoptosis and proliferation may be one of the major mechanisms of pathologic changes in UT.