engleski

Expression of the extracellular matrix molecules in the developing human striatum

The adult mammalian neostriatum is organized as complex mosaic of various anatomical and neurochemical compartments. Based on acetyl- cholinesterase histochemistry we can distinguish the striosomes and the surrounding matrix compartment. During development, histochemical and cytoarchitectonical inhomogenties observed in the striatum and referred as cell islands are more marked than the ones described in the adult brain. However, exact relationship between the fetal and adult modular organization, as well as the molecular mechanisms which control the aggregation of cells and fibers into striatal compartments are still unknown. As observed in rodents, the striosome and matrix cells may still segregate in the absence of dopamine afferents. Similarly, early destruction of striatal neurons does not seem to affect the compartmentalization of dopaminergic afferents in the developing striatum. These studies suggest that the cell surface and extracellular matrix (ECM) molecules play a crucial role in development of the striatal compartments. In a present study, we investigated expression of ECM markers in the developing human brain from 10 weeks postconception to 3 postnatal months using histochemistry for the PAS -alcian and immunohistochemical staining for fibronectin, syndecan 4, CS-56 and tenascin. In addition, we have compared the expression of these markers with the expression of the cellular, fibrilar and synaptic markers throughout the previously established periods of striatal development. The expression of the ECM molecules in the human striatum showed inhomogenous distribution that is synchronous with the transient organization of the developing striatum and with the growth of striatal afferents. Peak of ECM expression in the developing striatum is observed from the mid-fetal to the late pre-term period. In addition, ECM staining was the only examined marker we found to be localized in cell free perimeters surrounding cell islands in the developing brain. Gradual transition from fetal to mature ECM occurs during the first postnatal year.

striatum; human development; fetal; CNS patterning; tenascin; fibronectin

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