**Figure 2.** **Expression of heat shock proteins during ARPE-19 senescence.** (**A**) Immunoblot of HSP90α, HSP70, HSC70, BIP, HSPB1 (HSP27), HSPB5 (αB-crystallin) and β-actin in ARPE-19 cells treated with H_{2}O_{2} in the same way as Figure 1B. (**B**) Densitometry quantitation of protein bands in A in image J. The data shown are mean ± SD. The two-tailed unpaired *t*-test was used for statistical analysis (*n* = 3). (**C**–**G**) Quantitative PCR to measure the expression of HSP90α, BIP, HSC70, HSPB1 and HSPB5 in the cells treated with H_{2}O_{2} the same way as A. The data were from three independent experiments. The two-tailed unpaired *t*-test was used for statistical analysis (*n* = 3).