Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

Brazilian Journal of Medical and Biological Research

C.s. Bitencourt²  C.g. Duarte¹  A.e.c.s. Azzolini¹  A.i. Assis-pandochi¹ 

[1] ,Universidade de São Paulo Faculdade de Ciências Farmacêuticas de Ribeirão Preto Departamento de Análises Clínicas, Toxicológicas e BromatológicasRibeirão Preto SP ,Brasil

关键词: Thyroid hormone;    Complement system;    Alternative complement pathway;    Factor B;    T3;    T4;   

DOI  :  10.1590/S0100-879X2012007500028

来源: SciELO

【 摘 要 】

Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP) activity in male Wistar rats (180 ± 10 g) after altering their thyroid hormone levels by treatment with triiodothyronine (T3), propylthiouracil (PTU) or thyroidectomy. T3 and thyroxine (T4) levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg). Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01). In contrast, increased factor B concentration and activity (32%) were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License