title: Effects of low-level laser therapy on the serum TGF-β1 concentrations in individuals with autoimmune thyroiditis.
abstract: OBJECTIVE
  The objective of this study was to evaluate the serum concentration of transforming growth factor-β1 (TGF-β1) after low-level laser therapy (LLLT) in patients with hypothyroidism resulting from chronic autoimmune thyroiditis (CAT).
  
  
  BACKGROUND
  Certain data indicate that LLLT is effective in patients with hypothyroidism caused by CAT; however, the mechanisms of action of LLLT in thyroid tissue are unknown. Cytokines could play a role in the response to LLLT.
  
  
  METHODS
  A randomized, placebo-controlled trial included 43 patients with a history of levothyroxine therapy for CAT-induced hypothyroidism. The patients were randomly assigned to receive either 10 sessions of LLLT (830 nm, 50 mW output power, and 707 J/cm(2) fluence; L group, n=23) or 10 sessions of a placebo treatment (P group, n=20) twice a week. Levothyroxine was maintained at the same dose during the entire study period. TGF-β1 was measured both pre-intervention and 30 days post-intervention in both groups. The differences were calculated between the TGF-β1 values observed 30 days post-intervention and the pre-intervention TGF-β1 values for each group (intragroup).
  
  
  RESULTS
  Comparing the differences in TGF-β1 levels between the L group (874.9±541.7 pg/mL) and the P group (-128.4±832.8 pg/mL) revealed that there was a statistically significant increase in TGF-β1 levels 30 days post-intervention in group L compared with the placebo group (p=0.0379).
  
  
  CONCLUSIONS
  This finding suggested that the significant increase in serum TGF-β1 levels in patients with CAT-induced hypothyroidism was associated with the thyroid LLLT procedure. Future studies of the effect of LLLT on TGF-β1 gene expression in thyroid tissue are necessary to confirm these findings.
authors.affiliation: 1 Ultrasound Unit, Department of Radiology, Hospital das Clínicas, University of Sao Paulo Medical School , São Paulo, SP, Brazil .
authors.forename: Danilo B
authors.initials: DB
authors.lastname: Höfling
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Chavantes
authors.forename: Milena M P
authors.initials: MM
authors.lastname: Acencio
authors.forename: Giovanni G
authors.initials: GG
authors.lastname: Cerri
authors.forename: Suemi
authors.initials: S
authors.lastname: Marui
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Yoshimura
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Chammas
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D028022:Low-Level Light Therapy; D008297:Male; D008875:Middle Aged; D013967:Thyroiditis, Autoimmune / Q000532:radiotherapy*; D053773:Transforming Growth Factor beta1 / Q000097:blood*; D055815:Young Adult
chemical_list: D053773:Transforming Growth Factor beta1