Obrazac promena ekspresije hondroitin sulfatnih proteoglikana nakon ablacije senzomotornog korteksa kod mozga neonatalnih i odraslih pacova

Abstract

The central nervous system has a limited capacity for self-repair after damage. However, the neonatal brain has agreater capacity for recovery than the adult brain. These differences in the regenerative capability depend on local environmental factors and the maturational stage of growing axons. Among molecules which have both growth-promoting and growth-inhibiting activities is the heterogeneous class of chondroitin sulfate proteoglycans (CSPGs). In this paper, we investigated the chondroitin-4 and chondroitin-6 sulfate proteoglycan expression profile after left sensorimotor cortex ablation of the neonatal and adult rat brain. Immunohistochemical analysis revealed that compared to the normal uninjured cortex, lesion provoked up regulation of CSPGs showing a different pattern of expression in the neonatal vs. the adult brain. Punctuate and membrane-bound labeling was predominate after neonatal lesion, where as heavy deposition of staining in the extracellular matrix was observed after adult lesion. Heavy deposition of CSPG immunoreactivity around the lesionsite in adult rats, in contrast to a less CSPG-rich environment in neonatal rats, indicated that enhancement of the recovery process after neonatal injury is due to amore permissive environment.

Centralni nervni sistem ima ograničen kapacitet za oporavak nakon povrede. Međutim, neonatalni mozak pokazuje veću sposobnost oporavka u odnosu na odrasle. Ove razlike zavise od lokalnih sredinskih faktora i stepena zrelosti aksona tokom izrastanja. U grupu molekula koji mogu da stimulišu ili inhibiraju rast aksona spada i heterogena klasa molekula označena kao hondroitin sulfatni proteoglikani (CSPG). U ovom radu ispitivanje profil ekspresije hondroitin-4 i hondroitin-6 sulfatnih proteoglikana nakonlezije leve senzomotorne kore neonatalnog i adultnog mozga pacova. Imunohistohemijska analiza pokazuje da u odnosu na normalni,nepovređeni korteks, lezija dovodi do povećanja ekspresije CSPG koji ima različiti obrazac promena u neonatalnom u odnosu na adultni mozak. Nakonlezije kod mladih, predominiraju tačkasta i membranski-vezana forma, dok kod odraslih lezija dovodi do nagomilavanja CSPG u ekstra ćelijskom matriksu. Prohodnija sredina u mozgu neonatalnih pacova koja je siromašnija CSPG, preduslov je boljeg procesa oporavka u odnosu na adulte, kod kojih se nakon povrede CSPG nagomilavaju oko mesta lezije.