Curcumin protects against hypertension aggravated retinal ischemia/reperfusion in a rat stroke model

The pathogenesis of visual dysfunction in stroke remains unclear. The objective of this study was to explore retinal damage in stroke spontaneously hypertensive rats (SHR) and evaluate the role of curcumin in the retinal injury after stroke. Mature male SHR were used as the animal model for hypertension and age-matched male Wistar-Kyoto (WKY) rats as the normotensive controls. The rat model of stroke was made by bilateral vertebral artery electrocoagulation combined with transient bilateral common carotid artery ligation. The animals were randomly divided into sham group, ischemia/reperfusion group, solvent control group, and curcumin treatment group. Each group was subdivided into 2 h, 6 h, 24 h, 72 h, and 7 day after reperfusion. Blood pressure was measured in SHR and WKY rats. Eye fundus was examined in living animals, and then, tissue specimens were collected for histologic examination, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling, and immunohistochemistry. Retinopathy, induced by I/R, was more serious in rats with hypertension than that in normotensive rats (retinal thickness index, p = 0.004). The number of apoptosis in retinal capillary cells and neurons reduced significantly in the curcumin-treated groups. Curcumin treatment inhibited phosphorylated c-Jun N-terminal kinase (JNK) expression in SHR after retinal I/R injury. Thus, hypertension aggravated retinal I/R injury after stroke. Curcumin, a specific inhibitor of JNK, can prevent the development of hypertensive retinopathy after I/R injury by inhibiting apoptosis in retinal capillary cells and neurons.