TABLE 1.
Growth factor levels in conditioned media of murine retinal explantsa
| Growth factor | Concn (nM) ± SD |
|
|---|---|---|
| Normoxic (36 h) | Hypoxic (36 h) | |
| VEGF | 0.03 ± 0.01 | 0.18 ± 0.04 |
| PDGF-A | 0.03 ± 0.00 | 0.02 ± 0.00 |
| PDGF-AB | 0.03 ± 0.00 | 0.04 ± 0.01 |
| PDGF-B | 0.05 ± 0.02 | 0.04 ± 0.01 |
| PDGF-C* | 0.02 ± 0.01 | 0.03 ± 0.02 |
| PDGF-D* | ND | ND |
| EGF | 0.08 ± 0.02 | 0.07 ± 0.02 |
| FGF-2 | 0.06 ± 0.02 | 0.06 ± 0.03 |
| HGF | 0.17 ± 0.05 | 0.24 ± 0.08 |
| IGF-1 | 0.65 ± 0.18 | 0.48 ± 0.16 |
| IL-6 | 0.06 ± 0.08 | 0.11 ± 0.08 |
| TGF-α | ND | 0.02 ± 0.00 |
| CTGF | 0.06 ± 0.02 | 0.04 ± 0.01 |
| TGF-β1 | 0.13 ± 0.04 | 0.16 ± 0.07 |
| TGF-β2 | 0.88 ± 0.16 | 0.65 ± 0.10 |
| G-CSF | ND | ND |
Retinas were removed from P12 mouse pups, sectioned, and placed between two collagen layers in the presence of DMEM containing 0.1% serum. Explanted tissue was left to incubate overnight at 37¡C before conditioning the samples under normoxic (21% O2) or hypoxic (0.5% O2) conditions as described in Fig. 1. No exogenous growth factors were added during conditioning. At 36 h, 100 μl of the conditioned media was withdrawn from each explant and subjected to multiplex and semiquantitative Western blot analyses to determine the concentrations of a panel of 16 growth factors, chosen based on their ability to modulate (directly or indirectly) PDGFRα activation (5, 22). PDGF-D and G-CSF were not detected (ND) in the conditioned media from explants subjected to normoxic or hypoxic conditions. *, active form only.