Zelluläre Begleitreaktionen bei seit 30 Jahren bestehender Siderosis N. optici

Concentration change of TGF -β 1 in aqueous humor of rabbits

OBJECTIVE

To observe the influence of the the transforming growth factor β1 (TGF-β1) eye drops on rabbit aqueous humor TGF-β1 concentration, and to analyze the best drug concentration.

METHODS

A total of 30 New Zealand white rabbits were randomly divided into 5 groups with 6 in each. Rabits in control group had PBS eye drops, group A, B, C, D adopted TGF-β1 eye drops at 0.5, 1.0, 2.0, 4.0 mg/L, respectively, 4 times a day. Aqueous humor of right eye was extracted 1 week after administration to detect concentration changes of TGF-β1 by ELISA; rabbits in fpur hroups adopted 2.0 mg/L eye drops to left eyes 4 times a day, 0.2 mL aqueous humor was extracted left eye at the scheduled time point 0, 30 min, 2 h, 4 h, 24 h for testing, the slit lamp was used to observe the cornea, chamber and lens.

RESULTS

No obvious pathological changes in conjunctiva, cornea, rabbit conjunctival, anterior chamber, and the lens was found. Concentration of TGF-β1 in rabbit aqueous humor in C, D group was significantly higher than the control group (P<0.05).

CONCLUSIONS

TGF-β1 eye drops at 2.0 mg/L, 4.0 mg/L can significantly increase concentration of TGF-β1 in rabbit aqueous humor, withe good ocular surfac permeability.

Traumatology of the optic nerve and contribution of crystallins to axonal regeneration

Within a few decades, the repair of long neuronal pathways such as spinal cord tracts, the optic nerve or intracerebral tracts has gone from being strongly contested to being recognized as a potential clinical challenge. Cut axonal stumps within the optic nerve were originally thought to retract and become irreversibly necrotic within the injury zone. Optic nerve astrocytes were assumed to form a gliotic scar and remodelling of the extracellular matrix to result in a forbidden environment for re-growth of axons. Retrograde signals to the ganglion cell bodies were considered to prevent anabolism, thus also initiating apoptotic death and gliotic repair within the retina. However, increasing evidence suggests the reversibility of these regressive processes, as shown by the analysis of molecular events at the site of injury and within ganglion cells. We review optic nerve repair from the perspective of the proximal axon stump being a major player in determining the successful formation of a growth cone. The axonal stump and consequently the prospective growth cone, communicates with astrocytes, microglial cells and the extracellular matrix via a panoply of molecular tools. We initially highlight these aspects on the basis of recent data from numerous laboratories. Then, we examine the mechanisms by which an injury-induced growth cone can sense its surroundings within the area distal to the injury. Based on requirements for successful axonal elongation within the optic nerve, we explore the models employed to instigate successful growth cone formation by ganglion cell stimulation and optic nerve remodelling, which in turn accelerate growth. Ultimately, with regard to the proteomics of regenerating retinal tissue, we discuss the discovery of isoforms of crystallins, with crystallin beta-b2 (crybb2) being clearly upregulated in the regenerating retina. Crystallins are produced and used to promote the elongation of growth cones. In vivo and in vitro, crystallins beta and gamma additionally promote the growth of axons by enhancing the production of ciliary neurotrophic factor (CNTF), indicating that they also act on astrocytes to promote axonal regrowth synergistically. These are the first data showing that axonal regeneration is related to crybb2 movement within neurons and to additional stimulation of CNTF. We demonstrate that neuronal crystallins constitute a novel class of neurite-promoting factors that probably operate through an autocrine and paracrine mechanism and that they can be used in neurodegenerative diseases. Thus, the post-injury fate of neurons cannot be seen merely as inevitable but, instead, must be regarded as a challenge to shape conditions for initiating growth cone formation to repair the damaged optic nerve.