The repair of brain lesion by implantation of hyaluronic acid hydrogels modified with laminin

Abstract

The hyaluronic acid (HA) hydrogels modified with laminin were used for implantation in rat brain in present study, in order to investigate its effects in reparation of injury in the CNS. Cross-linked HA hydrogels were synthesized and their characteristics were analyzed. Laminin, an extracellular matrix protein, which participates in neuronal development and survival, was immobilized on the backbone of the hydrogels. Hydrogels unmodified and modified with laminin were implanted into cortical defects mechanically created in rats and their ability to improve tissue reconstruction was then evaluated. After 6 and 12 weeks of implantation, sections of brains were processed with Nissl and Glees staining for revealing neural cell bodies and fibers, with DAB histochemistry for detecting the blood vessels, as well as with immunocytochemistry for recognizing GFAP. The sections were also taken to SEM and TEM for ultrastructral examination. The results showed that the HA hydrogels synthesized had mechanical properties and rheological behavior similar to the brain tissue. After being implanted into the lesion of the cortex, the porous hydrogels created a scaffold, which could support cell infiltration and angiogenesis, and simultaneously inhibit the formation of glial scar. In addition, HA hydrogels modified with laminin could promote neurite extension. It seems possible that the tissue engineering technique may pave the way to repair injury in the CNS as suggested by the results in present study.