Citicoline and lithium rescue retinal ganglion cells following partial optic nerve crush in the rat.
ABSTRACT Citicoline and lithium (Li(-)) have been shown to support retinal ganglion cell (RGC) survival and axon regeneration in vitro. Optic nerve crush (ONC) is a model of both brain axonal injury and certain aspects of the glaucomatous degeneration of RGC. We have used this model to quantify protection offered to RGC by these drugs and to determine whether their effects are mediated by enhanced expression of the antiapoptotic protein Bcl-2. Adult rats (6-12 per group) were subjected to ONC accompanied by a contralateral sham operation. Animals were treated intraperitoneally with either vehicle, citicoline sodium (1g/kg daily for up to 7 days and 300 mg/kg daily afterwards), lithium chloride (30 mg/kg daily), or both drugs combined. Fluorogold was injected bilaterally into superior colliculi 1, 5 or 19 days after ONC. Labeled cells were counted under a fluorescence microscope 2 days after tracer injection. In a separate set of experiments the effects of treatments on expression of Bcl-2 in retinas were evaluated by immunohistochemistry. In vehicle-treated animals there was a progressive decrease of RGC density after crush. This decrease was attenuated in citicoline-treated animals 1 week and 3 weeks after the crush. In the lithium-treated group protection was even more pronounced. In animals treated with both drugs RGC protection was similar to that achieved by lithium alone. Bcl-2 immunoreactivity was seen predominantly in retinal ganglion cells. Its increase was recorded in the lithium and citicoline group as well as in animals treated with the combination of both drugs. Both citicoline and lithium protect RGC and their axons in vivo against delayed degeneration triggered by the ONC. Retinoprotective action of both drugs may involve an increase in Bcl-2 expression.
- [Show abstract] [Hide abstract]
ABSTRACT: Glaucoma often exists and progresses at normal or even low intraocular pressure (IOP) levels, on the basis of IOP-independent risk factors. Pressure-independent risk factors have only begun to be explored. Decreased perfusion of the optic nerve head may result from orthostatic hypotension, nocturnal hypotension, atrial fibrillation, migraine, Raynaud’s phenomenon, abnormally low intracranial pressure, autoimmune phenomena, and sleep apnea. Hemorheologic abnormalities, such as increased erythrocyte agglutinability, decreased erythrocyte deformability, increased serum viscosity, or increased platelet aggregability, may also play a role. Recent evidence has implicated oxidative stress as playing a significant role in retinal ganglion cell (RGC) damage in glaucoma. Gamma-aminobutyric acid (GABAA) receptors are expressed on RGCs and may play a role in apoptosis induced by oxidative stress.
- [Show abstract] [Hide abstract]
ABSTRACT: Neuroprotection of lithium for axotomized retinal ganglion cells (RGCs) is attributed to upregulated intraretinal Bcl-2. As lithium also upregulates brain-derived neurotrophic factor (BDNF) which can rescue axotomized RGCs, it is hypothesized that lithium could protect RGCs through BDNF. This study investigated this hypothesis and a possible relationship between the dose and protection of lithium. All adult experimental rats received daily intraperitoneal injections of lithium chloride (LiCl) at 30, 60 or 85 mg/kg·bw until they were euthanized 2, 7 or 14 days after left intraorbital optic nerve (ON) transection. Our results revealed that RGC densities promoted and declined with increased dose of LiCl and the highest RGC densities were always in the 60 mg/kg·bw LiCl group at both 7 and 14 day points. Similar promotion and decline in the mRNA and protein levels of intraretinal BDNF were also found at the 14 day point, while such BDNF levels increased in the 30 mg/kg·bw LiCl group but peaked in the 60 and 85 mg/kg·bw LiCl groups at the 7 day point. These findings suggested that lithium can delay the death of axotomized RGCs in a dose-dependent manner within a certain period after ON injury and such beneficial effect is interrelated with an upregulated level of intraretinal BDNF.International Journal of Molecular Sciences 01/2014; 15(8):13550-63. · 2.46 Impact Factor
Article: [Neuroprotective approaches.][Show abstract] [Hide abstract]
ABSTRACT: After introduction of vitreoretinal surgery more than 40 years ago, further development of the procedure involved a continuous reduction of potential toxic effects by irrigating solutions, endoillumination or mechanical manipulation. Recently, additional efforts were made to prevent neurodegeneration via pharmacological intervention. Taurine as additive for irrigating solutions can be considered as an example for neuroprotectants in vitreoretinal surgery. Approval of neuroprotective agents demands an increased effort for preclinical and clinical evaluation. To date, only few neuroprotective substances are used in clinical routine in the context of vitreoretinal surgery, however, experimental data suggest a high potential of various neuroprotective agents. The following article gives an overview of current neuroprotective approaches feasible for vitreoretinal surgery and a critical analysis of their clinical relevance.Der Ophthalmologe 09/2013; · 0.53 Impact Factor