Influence Of Geranylgeranylacetone On The Expression Of HSP70 In Retina Of Rats With Chronic IOP Elevation

ObjectiveGlaucoma, one of the world's leading causes of blindness, is characterized by progressive optic nerve damage with selective loss of retinal ganglion cells(RGCs). It has been postulated that apoptosis, a highly regulated process of cell death, is the final common pathway for RGCs in glaucoma which is not yet known. Intracellular expression of HSP70 has been demonstrated to protect cerebral neurons against heat shock, oxidative stress, apoptotic stimuli, excitotoxic insults, and ischemia-like conditions. Neurons of transgenic mice expressing HSP70 or those of rats injected with the herpes virus containing HSP70 gene also have been shown to be resistant to ischemia and seizures, which suggests that HSP70 is essential for neuroprotection. GGA, is a unique antiulcer drug that protects gastric mucosa without affecting gastric acid or pepsin secretion. Its cytoprotective effects have been found to correlate with the expression of HSPs in gastric mucosal cells induced by the systemic administration of GGA. GGA induces HSPs in numerous tissues including rat small intestine, liver, lung, kidney, and heart. We investigate in the current study whether HSP70 is induced in rat RGCs with systemic administration of GGA. We performed this experiment to reveal the protection of glaucoma to some degree, and we look forward to applying our findings to clinical treatment.Methods1. Rat model of chronic IOP elevation.Three superficial venous tributaries were burnt in rats with mitomycin.2. Hematoxylin-eosine staining.3. Research on protein expression of HSP70 in normal, chronic hypertension, using GGA retina.We detected protein expression of HSP70 by immunohistochemistry(IHC) was statistical with One-Way ANOVA by SPSS 13.0 software.Result1. Three superficial venous tributaries were burnt combined with mitomycin in rats establish the chronic IOP elevation.2. Immunohistochemistry, the expression of HSP70 was very faint immuno staining in normal retina. In the glaucomatous retina immunostaining for HSP70 was predominant in the inner retinal layers, mostly in the retinal ganglion cell layer and the inner nuclear.3. Compared with groups of high IOP, in GGA+1 days group of high IOP, the number of round syncytium big positive cells for HSP70 in ganglion cell layer began to increase. HSP70 was positively expressed in the ganglion cell layer in GGA+3 days group and GGA+7 days group of high IOP. In GGA+ocular hypertension for 14 days, the positive ganglion cells for HSP70 reduce.Conclusion1. HSP70 located at ganglion cell layer(GCL) and a litter at inner nuclear layer(INL) in retina of rats2. Systemic administration of GGA regulated the expression of HSP70 in retina of rats with chronic IOP elevation.