Effects of low-level laser therapy on the serum TGF-β1 concentrations in individuals with autoimmune thyroiditis

Photomed Laser Surg. 2014 Aug;32(8):444-9. doi: 10.1089/pho.2014.3716.


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 data: 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.

Trial registration: ClinicalTrials.gov NCT01129492.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Humans
  • Low-Level Light Therapy*
  • Male
  • Middle Aged
  • Thyroiditis, Autoimmune / radiotherapy*
  • Transforming Growth Factor beta1 / blood*
  • Young Adult


  • Transforming Growth Factor beta1

Associated data

  • ClinicalTrials.gov/NCT01129492