RESUMO
BACKGROUND: The overexpression of transforming growth factor-beta 1 receptor II (TGF-beta1RII) and transforming growth factor-beta 1 (TGF-beta1) ligand may be involved in the formation of a bulla. In this study, we tested if serum TGF-beta1 ligand levels correlated with the expression level of TGF-beta1RII and TGF-beta1 in bullous tissues from patients with spontaneous pneumothorax. MATERIAL AND METHOD: Bullous lung tissues and blood samples were obtained from 19 patients with spontaneous pneumothorax, 18 males and 1 female, aged 17 to 35 years old. The bullous tissues were obtained by video-assisted thoracic surgery (VATS), fixed in formalin, embedded in paraffin, and cut into 5~6micrometer thick slices. Sections were immunohistochemically stained with primary antibodies against TGF-beta1 or TGF-beta1RII, and serum levels of TGF-beta1 in patients and normal controls was measured by enzyme-linked immunosorbent assay (ELISA). RESULT: Of the 19 patients, 16 were TGF-beta1 positive and 10 were TGF-beta1RII positive. Among the 16 TGF-beta1 positives, 9 were also TGF-beta1RII positive. As seen previously, strong immunohistochemical staining of TGF-beta1RII and TGF-beta was detected in the boundary region between the bullous and normal lung tissues. Average TGF-beta1 blood levels of both TGF-beta1 and TGF-beta1RII positive patients was 38.36+/-16.2 ng/mL, and that of five controls was 54.06+/-15 ng/mL. CONCLUSION: These results suggest that overexpression of TGF-beta1 and TGF-beta1RII expression may be involved in the formation of bullae. TGF-beta1 blood levels in patients with primary spontaneous pneumothorax is lower than normal people, suggesting that the high level of local TGF-beta1 expression in the bullous tissue region, but not in the whole blood, may contribute more in the formation of bullae.