Achieving cellular resolution for in vivo retinal images of transgenic GFAP-GFP mice via image processing

Imidazolium salt (DBZIM) reduces gliosis in mice treated with neurotoxicant 2'-CH(3) -MPTP

We have recently identified a class of imidazolium salts (IMSs) with antioxidative property and can function as scavengers for radical oxygen species (ROS) [18]. Here, we investigate one of the IMSs, 1,3-bisbenzylimidazolium bromide (DBZIM), for its possible role in attenuating neurotoxicity and gliosis in the retina and the brain induced by a Parkinsonian neurtoxicant, methyl-4(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'-CH(3) -MPTP), which is a free radical generating agent. In this study, we employ a molecular retinal imaging method, which we recently developed in a transgenic mouse model expressing green fluorescent protein (GFP) under the control of glial fibrillary acidic protein (GFAP) promoter [14], to assess the efficacy of DBZIM, since currently no in vitro system with a sufficient complexity is available for accurately assessing a compound's efficacy. The longitudinal imaging results showed DBZIM can effectively suppress the neurotoxicant-induced retinal gliosis. Immunohistochemistry performed on the postmodern mouse brain confirmed that DBZIM also reduced striatal gliosis, and concomitantly attenuated the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). These findings suggest that DBZIM could be a useful small molecular compound for studying neurotoxicity and neuroprotection in the retina and the brain.

In vivo imaging of retinal gliosis: a platform for diagnosis of PD and Screening of anti-PD compounds

Parkinson's disease (PD) is the second most frequent degenerative disorder after Alzheimer's disease. It is characterized by the depletion of mesenchephalic dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and striatal dopamine. Oxidative stress plays a major role in the pathogenesis of Parkinson's disease where DA neurons are especially vulnerable to excessive production of the H2O2 reactive oxygen species. Unfortunately, the first clinical symptoms of PD occur after at least 60-80% of nigro-striatal dopaminergic neurons have lost their function. Therefore, early detection of PD is critical in slowing down the progression of the disease and enabling the development of therapeutic compounds which could intervene at an earlier stage. Here, we employ in vivo molecular imaging of astrocytic retinal gliosis in a transgenic mice to longitudinally monitor the progression of MPTP-induced PD. We have quantitatively evaluated, via this imaging platform, the efficacy of a synthetic antioxidant, 1,3- bisbenzylimidazolium bromide (DBZIM), in protecting the DA neurons and scavenging the ROS. We show here that MPTPinduced PD results in an upregulation of glial fibrillary acidic protein (GFAP), a marker for gliosis, by 36% relative to saline whereas gliosis is normalized in MPTP-induced PD mice treated with DBZIM.