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U. C. Welge-Lussen, A. Kampik, A. Yu; Antioxidants Prevent Free Radical Mediated Increase of AlphaB-Crystallin and HSP 27 in Cultured Astrocytes. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3683. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Reactive astrocytes in glaucomatous optic nerve changes are characterized by an increased expression of heat shock proteins such as heat shock protein 27 (Hsp27) and alphaB-crystallin. Previously, we could show that in vitro ischemia/reperfusion injury, hydrogen peroxide and transforming growth factor beta 2 (TGF-β2) increase the expression of these small chaperones. Actually, various antioxidants are used to cope with oxidative stress in glaucomatous disease. The goal of the present study was to determine the ability of various antioxidants to prevent the hypoxia/reoxygenation(H/R), hydrogen peroxide and TGF-β2 mediated increase of Hsp27 and alphaB-crystallin in cultured human astrocytes.
Cultured human astrocytes were incubated under hypoxic conditions (1% O2 for 4 hours) with subsequent reoxygenation (12 to 48 hours). Additionally, cells were treated with 1.0 ng/ml TGF-β2 for 12 to 48 hours and with 400-800 µm H2O2. Expression of of alphaB-crystallin and Hsp27 was examined by real-time PCR and western-blotting. To evaluate the effect of vitamin B1, B12, E, C, anthocyane and alpha lipoic acid cells were pre incubated with physiological concentrations before H/R, H2O2 and TGF-ß2 treatment
H/R, oxidative stress and TGF-ß treatment increased the expression of HSP27and alphaB-Crystallin. The effect of H/R and oxidative stress was abolished if cells were pre incubated with µm alpha lipoic acid and µm anthocyane. The effect of TGF-ß2 treatment on the expression of these small heat shcok proteins was reduced by these two antioxidants. In contrast preincubation of human astrocytes with vitamin B5, B12, C and E could not reduce the stress induced increase of Hsp27 and alphaB-crystallin.
The antioxidants anthocyane and alpha lipoic acid are capable to reduce the H/R, oxidative stress and TGF-ß mediated increase of Hsp27 and alphaB TGF-β2 in cultured ONH astrocytes. Therefore, the use of these antioxidants in glaucomatous patients may help to lower the incidence of characteristic changes in the optic nerve.
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