Absence of lung fibrosis in TGFβ1 overexpressing mice. Figure A shows haematoxylin and eosin staining of Tr+ TGFβ1 transgenic lung tissue. Of note was the absence of fibrosis in transgenic mice. To determine the molecular events underpinning this process we determined the expression of TGFβ1 (B), Type I receptor for TGFβ1 (C) and the TGFβ1 Type II receptor (D) by immunohistochemistry. As can be seen TGFβ1 and its receptors are present in abundance in lung tissue from these mice, indicating a normal TGFβ1 signalling cascade in Tr+ pulmonary tissue.