Evaluation of surfactant proteins A, B, C, and D in articular cartilage, synovial membrane and synovial fluid of healthy as well as patients with osteoarthritis and rheumatoid arthritis - Fig 1

Visualization of SP-A, SP-B, SP-C and SP-D by RT-PCR (A+B) and Western Blot (C+D). A: SP-A, SP-B, SP-C and SP-D are detected by RT-PCR in primary chondrocytes and immortalized cell lines [C28/I2 and TC28a2] and B: synovial membrane from autopsied persons aged from18 up to 90 years, (-) negative control (water); (+) positive control, plasmid DNA carrying the full-length gene for the respective surfactant proteins. All RT-PCR analyses show cDNA amplification for the relevant surfactant protein in comparison to 18s or GAPDH. Western immunoblots of all surfactant proteins derived from the C: articular joint from autopsied persons aged from18 up to 90 years and D: synovial fluid from autopsied persons aged from 18; 48 and 90 years. The proteins were separated by SDS-PAGE under reducing conditions and show distinct bands for all four investigated surfactant proteins at the specific molecular weights (SP A: 60kDa, SP B: 40kDa, and SP D: 43kDa). For SP-C three visibly bands at 16kDa and 26kDa were detected for articular joint and 8kDa for synovial fluid. Lung was used as (+) positive control.