Expression of growth factor mRNAs by human Tenon's capsule fibroblasts

By using the techniques of reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern hybridization, we demonstrated that human Tenon's capsule fibroblasts in primary cultures, express the messenger RNA (mRNA) transcripts encoding transforming growth factor-beta 1 (TGF-beta 1), basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF), but not those coding for aFGF and TGF-beta 2. Two PCR products were obtained for TGF-beta 1: a major fragment of 161 base pairs that corresponded to the expected size, and a minor sequence of 400 base pairs. An antisense oligonucleotide probe specific for TGF-beta 1 detected only the band of 161 base pair of PCR-amplified sequence. For bFGF, PDGF-A and PDGF-B, we obtained only a single PCR product with the anticipated length of 222, 225, and 217 base pairs, respectively. Southern blotting experiments revealed that these PCR-amplified fragments were specific for the respective growth factors. The negative control experiments without template did not reveal any amplification. No product for aFGF or TGF-beta 2 was detected. By radioimmunoassay, TGF-beta 1 protein was detected at the level of 24-30 pg ml-1 per 2 million Tenon's fibroblasts during a 24-hour period in acid-activated conditioned medium. These results indicate that human Tenon's capsule fibroblasts in primary cultures express TGF-beta 1 at the translational as well as at the transcriptional levels, and they also have the capacity to synthesize bFGF and PDGF. Considering the significant effects of bFGF, TGF-beta 1, and PDGF in wound healing response, these growth factors are implicated in tissue repair process after glaucoma filtration surgery that contributes to the failure of the procedure.