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Research (running projects, previous projects)

A peripheral nerve injury including the disconnection of the spinal neurons with the target tissue is a frequent consequence of a trauma or surgical removal of tumors. Research projects include a broad range of studies at the molecular and cellular levels to elucidate the mechanisms responsible for axonal growth during development and regeneration in the nervous system. It is well known that in the peripheral nervous system certain reparative processes occur due to suitable microenvironment formed mainly by Schwann cells. The Schwann cells are able to provide conditions stimulating axonal regeneration not only in the peripheral, but also central nervous system. Understanding of the cellular and extracellular microenvironments, that stimulate recovery of connections among neurons or between neurons and peripheral target structures, is of considerable importance for encouragement of these processes in clinical practice (neurology, neurosurgery).

Methods used for the studies:

histological, histochemical and immunohistochemical analysis of glial cells relations after experimental treatments

mapping of neuronal connections by methods of retrograde transport of labeled molecules

quantitative assessment of above mentioned methods by means of image analysis

short-term cultures in vitro of Schwann cells

Running projects:

Description of the project

Changes are present in the spinal ganglia following total or partial axotomy of afferent axons. In addition, the spinal ganglia are invaded by sympathetic collateral sprouts that frequently form basket-like structures around the afferent neurons. The sympathetic collateral sprouts are referred to be related with neuropathic pain. Besides intrinsic neuronal changes there are signals of the satellite cells and their extracellular matrix stimulating a growth of sympathetic sprouts into the spinal ganglia. The aim of the present project is to investigate immunohistochemical changes in the satellite cells and their extracellular matrix content following total or partial axotomy of afferent axons at different levels. We use rat model of the central and peripheral axotomy, root compression, and transection and compression of the sciatic nerve. We will search immunohistochemical changes in the satellite cells (e.g., GFAP, TGFα, p75 receptor, cGMP) and their extracellular matrix (e.g., laminins, fibronectin, tenascin) of the ipsilateral and contralateral ganglia of axotomized and intact rats. Quantitative immunohistochemistry of investigated molecules by image analysis may disclose possible extrinsic mechanisms for stimulation of sympathetic sprouts and their contribution to neuropathic pain.

Previous projects:

Description of the project

Extracelular matrix (ECM) of the Schwann cells (SC) and derived auxiliary structures play an important role during the reparative processes in the peripheral nervous system (PNS). Integrins, which ensure interactions between the cell and ECM, may be of significant importance for transfer of morfogenous information from ECM during differentiation of SC and derived structures. The glial cells of the PNS are of various shapes and form the basal lamina at their surface during differentiation. The aim of the project is to prove: i/ sequence of integrin expression during differentiation of the PNS glia in the prenatal and early postnatal period, ii/ relation between the shape of the glia and integrin expression, iii/ function of integrins during ECM effect to re-differentiation of migrated non-differentiated SC in the adult organism in absence of the nerve component, iv/ role of integrins during migration and differentiation of SC in artificial matrix in absence of the nerve component. Stated aims will be accomplished by immunohistochemical study of integrin expression in prenatal and early postnatal developmental stages.

Description of the project

Axonal regeneration is possible in mammalian peripheral nerves in contrast to the CNS. Injured peripheral nerve provides external conditions for axonal regeneration during the Wallerian degeneration, when non-differentiated Schwann cells synthesize molecules stimulating axonal growth. The renewed synthesis of the molecules combined with suitable composition of the extracellular matrix are main external factors influencing axonal regeneration in the peripheral nerve system. Existing knowledge suggests that the cellular and molecular conditions for motor and somatosensory axons may not be same in the injured nerve; moreover, further differences might be expected in comparison of conditions for axonal regeneration distal to lesion of the spinal roots with those distal to lesion of the peripheral nerve. The aim of the project is to compare cellular and extracellular conditions for regeneration of motor and somatosensory axons, which appear after transection of spinal roots and peripheral nerves in the rat.
 

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Tento server byl naposledy aktualizován dne 18. 11. 2003