Neovascularization in kainic acid-induced lesions of rat striatum. An immunohistochemical study with laminin.

Vascular changes occurring after stereotaxic injection of the excitatory neurotoxin kainic acid (KA) into the rat striatum were studied at various time intervals after the lesion using laminin immunohistochemistry. Laminin immunohistochemistry revealed marked vascular changes, including presumed neovascularization, in the lesioned striatum. Vessels with increased laminin immunoreactivity were demonstrated from 2 days up to at least 5 months following the injection. The majority was capillary vasculature, which was distributed throughout the lesioned striatum, sometimes being arranged densely along the needle tract. Fine spike-like sprouts called streamers were also loaded with laminin immunoreactivity. In contrast, laminin immunoreactivity in vessels in the control striatum was negligible. Vascular changes detected by laminin immunohistochemistry preceded but then almost paralleled gliosis demonstrated by glial fibrillary acidic protein immunohistochemistry. These results indicate that striatal injection of KA causes marked vascular changes including neovascularizations which are demonstrable by laminin immunohistochemistry.