OBJECTIVETo explore the changes in the expressions of glial fibrillary acidic protein (GFAP) and growth- associated protein-43 (GAP-43) in retinal ganglial cells after neural transplantation.

METHODSThirty-nine rats were randomized into normal control group, nerve amputation group and nerve amputation with peripheral nerve transplantation group. Immunohistochemistry was used to detect the changes in the expressions of GFAP and GAP-43 at different time points after the operations, and real-time PCR was employed to detect the mRNA expressions of 13 genes in the retinal ganglial cells of the rats.

RESULTSImmunohistochemistry showed obviously increased GFAP expressions in the retina following the nerve amputation. GFAP expression was down-regulated while GAP-43 expression upregulated in the retinal ganglial cells after peripheral nerve transplantation. Real-time PCR results showed that 5 days after the operations, retinal GFAP and GAP-43 expressions increased significantly in the nerve amputation group and peripheral nerve transplantation groups as compared with those in the control group, but GAP-43 expression decreased significantly in the former two groups afterwards.

CONCLUSIONThe regenerated retina may adjust the production of GFAP. The retinal ganglial cells express GAP-43 during retinal regeneration. Up-regulation of the expression of GAP-43 provides the evidence for nerve regeneration following the nerve transplantation.

Animals ; Axons ; Female ; GAP-43 Protein ; genetics ; metabolism ; Glial Fibrillary Acidic Protein ; genetics ; metabolism ; Nerve Regeneration ; genetics ; Optic Nerve ; transplantation ; Optic Nerve Injuries ; metabolism ; Random Allocation ; Rats ; Retinal Ganglion Cells ; metabolism

OBJECTIVE: To observe the change of retinal ganglion cells (RGCs)and the expression of Bad after optic nerve injury, so as to study the changes of optic function level on morphology and molecular. METHODS: The experimental models of optic nerve crush were established in fifty Wistar rats. At the different time after injuries (from one to twenty-eight day), the changes of RGCs were observed under microscope. Immunohistochemiscal technique and computer image analysis methods were performed to observe the changes of Bad in RGCs in rats. RESULTS: The number of RGCs was reduced significantly according to partial lesion of optic nerve crush. An initial loss of RGCs densities was accelerated in one week after nerve crush, two weeks later the trend mitigated. After four weeks, no obvious change were observed. The expression of Bad increased in 3 days, reached peak in 5 days, and declined one week later. No obvious changes were observed after two weeks. CONCLUSION The expression of Bad lead to the loss of RGCs following optic nerve crush. This is the important reason of loss optic function. The identification on optic nerve injuries should be done at least four weeks later.
Animals ; Cell Death ; Disease Models, Animal ; Female ; Forensic Medicine ; Male ; Nerve Crush ; Optic Nerve/physiopathology* ; Optic Nerve Injuries/pathology* ; Random Allocation ; Rats ; Rats, Wistar ; Retinal Ganglion Cells/pathology* ; Time Factors ; bcl-Associated Death Protein/metabolism*

OBJECTIVE: To investigate the therapeutic effect of Epothilone D on traumatic optic neuropathy (TON) in rats. METHODS: Forty-two SD rats were randomized to receive intraperitoneal injection of 1.0 mg/kg Epothilone D or DMSO (control) every 3 days until day 28, and rat models of TON were established on the second day after the first administration. On days 3, 7, and 28, examination of flash visual evoked potentials (FVEP), immunofluorescence staining and Western blotting were performed to examine the visual pathway features, number of retinal ganglion cells (RGCs), GAP43 expression level in damaged axons, and changes of Tau and pTau-396/404 in the retina and optic nerve. RESULTS: In Epothilone D treatment group, RGC loss rate was significantly decreased by 19.12% (P=0.032) on day 3 and by 22.67% (P=0.042) on day 28 as compared with the rats in the control group, but FVEP examination failed to show physiological improvement in the visual pathway on day 28 in terms of the relative latency of N2 wave (P=0.236) and relative amplitude attenuation of P2-N2 wave (P=0.441). The total Tau content in the retina of the treatment group was significantly increased compared with that in the control group on day 3 (P < 0.001), showing a consistent change with ptau-396/404 level. In the optic nerve axons, the total Tau level in the treatment group was significantly lower than that in the control group on day 7 (P=0.002), but the changes of the total Tau and pTau-396/404 level did not show an obvious correlation. Epothilone D induced persistent expression of GAP43 in the damaged axons, detectable even on day 28 of the experiment. CONCLUSION Epothilone D treatment can protect against TON in rats by promoting the survival of injured RGCs, enhancing Tau content in the surviving RGCs, reducing Tau accumulation in injured axons, and stimulating sustained regeneration of axons.
Animals ; Disease Models, Animal ; Epothilones ; Evoked Potentials, Visual ; Nerve Regeneration/physiology* ; Optic Nerve Injuries/metabolism* ; Rats ; Rats, Sprague-Dawley ; Retinal Ganglion Cells/physiology*

BACKGROUNDCurrently, no medicine is available that can prevent or treat neural damage associated with optic nerve injury. Minocycline is recently reported to have a neuroprotective function. The aims of this study were to exarmine the neuroprotective effect of minocycline on retinal ganglion cells (RGCs) and determine its underlying mechanisms, using a mouse model of optic nerve crush (ONC).

METHODSONC was performed in the left eye of adult male mice, and the mice were randomly divided into minocycline-treated group and saline-treated control group. The mice without receiving ONC injury were used as positive controls. RGC densities were assessed in retinal whole mounts with immunofluorescence labeling of βIII-tubulin. Transmission electron microscopy was used to detect RGC morphologies, and Western blotting and real-time PCR were applied to investigate the expression of autophagy markers LC3-I, LC3-II, and transcriptional factors nuclear factor-κB1 (NF-κB1), NF-κB2.

RESULTSIn the early stage after ONC (at Days 4 and 7), the density of RGCs in the minocycline-treated group was higher than that of the saline-treated group. Electron micrographs showed that minocycline prevented nuclei and mitochondria injuries at Day 4. Western blotting analysis demonstrated that the conversion of LC3-I to LC3-II was reduced in the minocycline-treated group at Days 4 and 7, which meant autophagy process was inhibited by minocycline. In addition, the gene expression of NF-κB2 was upregulated by minocycline at Day 4.

CONCLUSIONThe neuroprotective effect of minocycline is generated in the early stage after ONC in mice, partly through delaying autophagy process and regulating NF-κB2 pathway.

Animals ; Autophagy ; drug effects ; Male ; Mice ; Minocycline ; therapeutic use ; NF-kappa B p52 Subunit ; metabolism ; Optic Nerve Injuries ; drug therapy ; metabolism ; Retinal Ganglion Cells ; drug effects ; metabolism

OBJECTIVETo explore the effect of kallikrein-binding protein (KPB) in protecting retinal ganglion cells (RGCs) and promoting axonal regeneration following optical nerve injury in rats.

METHODSCrush injury of the optic nerve at 0.5-1.0 mm from the eyeball was induced in rats, which received subsequent KBP injection into the vitreous cavity (experimental group) and PBS injection (control group). At 7, 14 and 21 days after the injury, the rats were sacrificed and frozen sections of the eyeball were prepared to observe the structure and thickness of the retina and count the number of survival RGCs with HE staining. The optic nerves were collected for Western blotting to assess the effect of KBP on the RGCs and axonal regeneration.

RESULTSRGC counts and retinal thickness showed significant differences between the two groups. Western blotting also demonstrated a significant difference in the expression of the nerve regeneration marker protein GAP-43 between the two groups.

CONCLUSIONKBP offers protection on RGCs and promotes regeneration of the optic nerve axons after optic nerve injury in rats.

Animals ; Axons ; physiology ; Female ; GAP-43 Protein ; metabolism ; Nerve Regeneration ; drug effects ; physiology ; Neuroprotective Agents ; pharmacology ; Optic Nerve Injuries ; drug therapy ; Rats ; Rats, Sprague-Dawley ; Retinal Ganglion Cells ; drug effects ; physiology ; Serpins ; pharmacology

BACKGROUNDOptic nerve injury, caused by retinal and optic nerve diseases, can eventually result in vision loss. To date, few effective treatments have been discovered to restore visual function. Previous studies showed that recombinant human erythropoietin (rhEPO) has a neuroprotective effect on the central nervous system, particularly in nerve injury. In this study, we investigated the effects of rhEPO on axonal regeneration and functional restoration following optic nerve injury. This was done by measuring the expression of growth associated protein 43 (GAP-43), a marker for neuronal regeneration, on the retina and flash-visual evoked potential (F-VEP).

METHODSAdult Wistar rats were randomly assigned to rhEPO and control (saline) groups. Optic nerve crush injury models were established and rhEPO or saline were immediately injected into the vitreous cavity. The expression of GAP-43 was detected by immunohistochemistry and the F-VEP was measured pre-injury, immediately after injury, 1 week and 2 weeks post-injury.

RESULTSNo detectable staining for GAP-43 was observed in normal retina. In the control group, the level of GAP-43 expression was higher at 1 week post-injury, but decreased at 2 weeks. In the rhEPO group, the level of GAP-43 expression was notably higher at both 1 week and 2 weeks. At each time point post-injury, the expression of GAP-43 in rhEPO group was significantly higher than the control group (P < 0.05). Obvious changes in F-VEP examination were detected immediately after optic nerve injury, including significantly prolonged latency and decreased amplitude of the P1 wave. In the control group, the changes were still obvious at 1 week. The latency was decreased and the amplitude had slightly recovered to 28.23% of the normal value at 2 weeks. In rhEPO group, there was significantly more recovery than the control group at 1 week and 2 weeks post-injury (P < 0.05). The latency most close to the normal level and the amplitude had recovered to 65.51% of the normal value at 2 weeks.

CONCLUSIONSrhEPO can prolong the expression of GAP-43 and increase its intensity after optic nerve injury, thereby promoting neural repair and axonal regeneration. Under the protection of rhEPO, the conduction velocity of the optic nerve recovered significantly. Therefore, rhEPO has neuroprotective effects on the optic nerve and promotes functional restoration of the optic nerve.

Animals ; Erythropoietin ; pharmacology ; therapeutic use ; Evoked Potentials, Visual ; drug effects ; GAP-43 Protein ; metabolism ; Humans ; Immunohistochemistry ; Neuroprotective Agents ; pharmacology ; therapeutic use ; Optic Nerve ; drug effects ; Optic Nerve Injuries ; drug therapy ; Random Allocation ; Rats ; Rats, Wistar ; Recombinant Proteins ; Retina ; drug effects ; metabolism