Figure 6. Preconditioning by LPS-induced TLR4 activation protects photoreceptors from oxidative stress.

(A) Muller glia-photoreceptor cultures were incubated in LPS (0.05–50 µg/ml) two hrs before challenge with 0.4 mM H₂O₂. Significant protection was seen with 0.5 and 5 µg/ml LPS (*p<0.05 vs no LPS). Mean ± SD, n = 4. (B) Wnt3a (150 ng/ml) also protected photoreceptors (*p<0.05 compared with no additions). The combination of Wnt3a and 0.5 and 5 µg/ml LPS preconditioning had greater protection than Wnt3a alone (#p<0.05 vs Wnt3a). Mean ± SD, n = 4. The comparison between Wnt3a+5 µg/ml LPS vs Wnt3a+50 µg/ml LPS, Wnt3a+0.5 µg/ml LPS vs Wnt3a+5 µg/ml LPS, and Wnt3a+50 µg/ml LPS vs no additions, are also significant at p<0.05. Viability was measured by Cell Titer Blue.