Expression of glucocorticoid receptor alpha and beta mRNA in orbital tissues in thyroid associated ophthalmopathy

Abstract

To evaluate the expression of glucocorticoid receptor alpha (GRalpha) and beta (GRbeta) messenger RNA (mRNA) in orbital tissues from thyroid associated ophthalmopathy (TAO). Samples of extraocular muscle and orbital fat were obtained from 17 patients with TAO and 10 healthy individuals. Total RNA was extracted and reversely transcripted into cDNA. The expression of GRalpha and GRbeta mRNA was detected by means of fluorescent quantitative polymerase chain reaction (PCR). Expression of GRalpha mRNA was much higher than GRbeta mRNA in all extraocular muscle and orbital fat biopsies. The relative copy of GRalpha was 40.15 +/- 11.37 in TAO patients and 20.64 +/- 7.07 in the controls. GRalpha: GRbeta mRNA ratio of these two groups was 77.76 +/- 18.77 and 148.34 +/- 23.86, respectively. There was significant difference between these two groups (P < 0.05). No significant difference was noted between extraocular muscle and orbital fat biopsies, between glucocorticoid-treated and non-treated patients or among hyperthyroidism, hypothyroidism and euthyroidism (P > 0.05). The increased expression of GRalpha mRNA and decreased GRalpha: GRbeta ratio in orbital tissues may play an important role in the pathogenesis of TAO and the effects of glucocorticoid treatment.