ABSTRACT
Purpose: Neurons carry electrical signals and communicate via electrical activities. The therapeutic potential of electrical stimulation (ES) for the nervous system, including the retina, through improvement of cell survival and function has been noted. Here we investigated the neuroprotective and regenerative potential of ES in a mouse model of inherited retinal degeneration. Methods: Rhodopsin-deficient (Rho-/-) mice received one or two sessions of transpalpebral ES or sham treatments for 7 consecutive days. Intraperitoneal injection of 5-ethynyl-2'-deoxyuridine was used to label proliferating cells. Weekly electroretinograms were performed to monitor retinal function. Retinal morphology, photoreceptor survival, and regeneration were evaluated in vivo using immunohistochemistry and genetic fate-mapping techniques. Müller cell (MC) cultures were employed to further define the optimal conditions of ES application. Results: Noninvasive transpalpebral ES in Rho-/- mice improved photoreceptor survival and electroretinography function in vivo. ES also triggered residential retinal progenitor-like cells such as MCs to reenter the cell cycle, possibly producing new photoreceptors, as shown by immunohistochemistry and genetic fate-mapping techniques. ES directly stimulated cell proliferation and the expression of progenitor cell markers in MC cultures, at least partially through bFGF signaling. Conclusions: Our study showed that transpalpebral ES improved photoreceptor survival and retinal function and induced the proliferation, probably photoreceptor regeneration, of MCs; this occurs via stimulation of the bFGF pathways. These results suggest the exciting possibility of applying noninvasive ES as a versatile tool for preventing photoreceptor loss and mobilizing endogenous progenitors for reversing vision loss in patients with photoreceptor degeneration.
Subject(s)
Disease Models, Animal , Electric Stimulation Therapy , Photoreceptor Cells, Vertebrate/cytology , Retinal Degeneration/therapy , Retinal Ganglion Cells/physiology , Animals , Cell Cycle/physiology , Cell Differentiation/physiology , Cell Proliferation/physiology , Cell Survival/physiology , Cells, Cultured , Electroretinography , Ependymoglial Cells , Immunohistochemistry , In Situ Nick-End Labeling , Mice , Mice, Knockout , Retinal Degeneration/genetics , Retinal Degeneration/physiopathology , Rhodopsin/geneticsABSTRACT
On the basis of preclinical and clinical evidence, statins lead to risk reduction of several types of neoplasia including breast cancer. This study is the first report on the preventive effects of fluvastatin in experimental breast cancer in vivo. In this experiment, the antineoplastic effects of fluvastatin in the chemoprevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated. The effects of fluvastatin on selected parameters of apoptosis, proliferation, and angiogenesis in mammary tumor cells were determined. The drug was dietary administered at two concentrations of 20 and 200 mg/kg. The experiment was terminated 17 weeks after carcinogen administration; mammary tumors were removed and prepared for histomorphological and immunohistochemical analysis. The basic parameters of experimental carcinogenesis, chosen metabolic variables, and side effects after long-term fluvastatin treatment in animals were assessed. Fluvastatin at higher concentrations suppressed tumor frequency by 63% and tumor incidence by 33% in comparison with the controls. After fluvastatin treatment, immunohistochemical analysis of tumor cells showed a decrease in vascular endothelial growth factor receptor-2 expression by 86% and an increase in caspase-3 by 8.5%. Fluvastatin in both treated groups significantly increased the parameters of serum lipid metabolism and significantly decreased femur compact bone thickness and body weight in animals. Our results suggest that fluvastatin and other statins should be further evaluated for tumor-preventive characteristics.
