Thyroid hormone nuclear receptor expression and its relation with injury severity in patients with severe multiple trauma

Abstract

Objective To investigate thyroid hormone nuclear receptor expression in peripheral blood mononuclear cells (PBMCs) and its relation with injury severity in patients with severe multiple trauma. Methods Twenty-eight patients with severe multiple trauma and another 26 healthy subjects as control were enrolled in the study. At 2 days after injury, the levels of free triiodothyronine (FT3) , free thyroxine (FT4) and thyroid-stimulating hormone (TSH) in peripheral venous blood were determined by using immunoradiometry, and the expressions of mRNA of the thyroid nuclear receptors (TRα and TRβ) in PBMCs were measured by using real-time RT-PCR. Results FT3 concentration in peripheral venous blood was significantly decreased in patients with severe multiple trauma versus healthy subjects. Concurrently, the expressions of TR mRNA (TRα and TRβ) were significantly decreased in PBMCs of patients with severe multiple trauma compared with healthy subjects (TRα mRNA: 3.86±0.54 vs. 5.24±1.17, P<0.05; TRβ mRNA: 9.86±2.27 vs. 13.57±2.45, P<0.05). Pearson correlation analysis showed that FT3 concentration and the expression of TRβ mRNA correlated negatively with injury severity score (ISS) in patients with severe multiple trauma (r=-0.445, -0.496, P=0.018, 0.007). Conclusions These data provide the evidence of a lowered activity of the thyroid signaling pathway in PBMC and a significantly negative correlation between FT3 concentration and the expression of TRβ mRNA in respect of injury severity in patients with severe multiple trauma. Additional investigations are needed to further determine the roles of the thyroid signaling pathway in adverse outcomes in the wake of severe multiple trauma. Key words: Severe multiple trauma; Injury severity score; Thyroid hormone receptor; Peripheral blood mononuclear cells