Demonstration of thyrotropin receptor mRNA in orbital fat and eye muscle tissues from patients with Graves' ophthalmopathy by in situ hybridization

There is a controversy regarding whether there are thyrotropin (TSH) recept ors in orbital fat and eye muscle tissues that may play a role in the patho genesis of Graves' ophthalmopathy. To elucidate whether there are TSH recep tors in orbital fat and eye muscle tissues in patients with Graves' ophthal mopathy, we applied the method of in situ hybridization in orbital fat and eye muscle tissues obtained during the operation for patients with Graves' ophthalmopathy, to directly detect TSH receptor mRNA. To identify whether t he cells with positive TSH receptor mRNA are fibroblasts, we also did vimen tin immunoreactivity study. To further prove the transcript does have a ful l length of TSH receptor, the samples of total RNA preparations, extracted from orbital fat and eye muscle tissues, were used as a template for revers e transcriptase polymerase chain reaction (RT-PCR) using three primer sets to generate cDNA fragments and cloned for sequencing. The results showed th at the expression of TSH receptor mRNA was demonstrated in adipocytes and f ibroblasts of orbital fat, and perimysial fibroblasts within eye muscle tis sues by in situ hybridization and vimentin immunoreactivity study. Also, by using the RT-PCR, cloning and sequencing, we further proved that the trans cript does have a full length of TSH receptor. The present study suggested that there are TSH receptors expressed in orbital fat and eye muscle tissue s. (J. Endocrinol. Invest. 22: 289-295, 1999) (C)1999, Editrice Kurtis.