The Mechanism Study On The Long Isofrom Opal In The Retinal Ischemia/Reperfusion Injury

Mitochondria are the crucial power plants of the cell. Under normal condition, mitochondria continually fuse and divide to form a dynamic network, and these processions are finely tuned. Opal is a critical protein that regulates mitochondrial inner-membrane fusion. The maintenance of Opal normal level is essential for mitochondrial fusion and function.Retinal ischemia/reperfusion (I/R) injury participates into many retinal disorders, including glaucoma, diabetic retinopathy, and traumatic optic neuropathy, etc. Retina is a part of central nervous system (CNS), and similar mechanisms are shared in retinal injury and CNS injury.Neuronal cells are extremely sensitive to mitochondrial dysfunction and impairment due to hardly mitosis or differentiate after maturation and the high demand of energy. In the present study, we found retinal I/R injury and hypoxia/reoxygenated (H/R) injury of cultured neuronal cells both dramatically induced Opal cleavage and caused loss of Opal long isoforms (L-Opal). Intravitreal injection of carbonylcyanide m-chlorophenyl hydrazone (CCCP) also induced L-Opal loss and retinal neurodegeneration. Whereas restoration of L-Opal level by overexpression of Opal-△S 1 (S1 cleavage site deletion Opal splice 1) not only normalized the H/R-induced mitochondrial morphology changes, but also inhibited the H/R-induced apoptosis, necrosis and the intracellular ATP loss. Furthermore, recovering L-Opal level in the I/R injured retina by intravitreal injection of genipin (a UCP2 inhibitor) or overexpression of Opal-△S1, inhibited the injury-induced retinal apoptosis and necrosis, cell loss in the ganglion cell layer and retinal thickness reduction. Together, our data demonstrated that the loss of L-Opal is involved in the pathogenesis of retinal I/R injury, and also indicates restoring L-Opal level may be considered as a therapeutic way to prevent I/R injury related diseases, at least for the retina.GLP-1(28～36) is the product of GLP-1 degrdation in vivo. In our research, we found GLP-1 (28～36) inhibited the retinal I/R injury-induced the changes of mitochondrial dynamic proteins, ER stress and neuronal degeneration. GLP-1(28～36) also inhibited the H/R injury-induced upregulation of inflammatory cytokines in cultured neuronal cells. These data indicated that GLP-1 (28～36) has neuroprotective effects.In this thesis, we have explored the pathogenesis and therapeutic medicine of retinal I/R injury, especially on the aspect of abnormal mitochondrial dynamic induced by I/R injury. Understanding the mechanism underline retinal I/R injury can provide us with clinically effective treatments for many retinal diseases and even many CNS disorders.