Experimental Modeling of Cranial Injury and Defect Reconstruction Using Superconstructive Polymers (PEEK).

Experimental model of resection craniotomy with subsequent reconstruction of the defect with a polymer implant enables comprehensive assessment of functional and ultrastructural changes during replacement of the damaged tissue. Reconstruction of a skull defect was accompanied by transient motor disturbance in the acute period and did not cause functional disorders and neurological deficits in a delayed period. Histological examination of osteal and brain tissue revealed no pathological reactions that could be associated with the response to the chemical components of the implant.

Neuroprotective and antiamnestic effect of nerve growth factor dipeptide mimetic GK-2 in experimental ischemic infarction of brain cortex.

The neuroprotective and antiamnestic effects of GK-2 dipeptide (nerve growth factor mimetic) were studied on rats with photoinduced bilateral focal ischemia of the prefrontal cortex. Intraperitoneal injection of GK-2 in a dose of 1 mg/kg on days 1, 2, 4, and 6 postoperation led to a 62% reduction of cortical infarction volume on day 9 and completely preserved conditioned passive avoidance response trained before stroke.

Formation of spatial memory in rats with ischemic lesions to the prefrontal cortex; effects of a synthetic analog of ACTH(4-7).

Photochemically induced thrombosis of blood vessels in the prefrontal cortex in rats was shown to lead to ischemic infarcts in the lesion zone. Bilateral ischemic lesioning of the prefrontal cortex degraded measures of spatial memory when animals were tested in a Morris water maze with an invisible platform 20-24 days after surgery. Chronic intranasal administration of the peptide Met-Glu-His-Phe-Pro-Gly-Pro (Semax), a synthetic analog of ACTH(4-7), at a dose of 250 microg/kg/day during the first six days after photothrombosis, led to recovery of the animals' learning ability. The long-term antiamnestic action of the peptide observed here may result from its neuroprotective activity and its ability to stimulate the synthesis of neurotrophic factors.

The role of cell fusion in physiological and reparative regeneration of the cerebral cortex.

The prefrontal (cognitive) cerebral cortex of rats was studied by morphological and physiological methods 56 days after stroke induced by photothrombosis. The cognitive capacity impaired after the intervention was completely restored by this time. The count of fused cells (dikaryons) increased significantly in experimental and sham-operated (control) animals in comparison with the early period (7 days) after surgery. Normalization of the dikaryon and mononuclear cell structure was observed after 56 days. Presumably, cell fusion promotes their morphological restoration and regeneration of the lost functional capacity. Fusion is regarded as a manifestation of physiological and reparative regeneration of the cortex.

Neuroprotective effect of afobazole on rats with bilateral local photothrombosis of vessels in the prefrontal cortex.

We studied the neuroprotective effect of a new selective anxiolytic afobazole on rats with bilateral focal ischemic stroke in the prefrontal cortex caused by photothrombosis. Intraperitoneal injection of 5 mg/kg afobazole 1 h after surgery and over the next 8 days (daily treatment) produced a neuroprotective effect. Afobazole was far superior to the reference cerebroprotective drug cavinton (4 mg/kg) by neuroprotective activity.

Impairment of learning and memory after photothrombosis of the prefrontal cortex in rat brain: effects of Noopept.

Experiments were performed on rats trained conditioned passive avoidance response. Acquisition and retention of memory traces were impaired after photothrombosis of the prefrontal cortex. The acyl-prolyl-containing dipeptide Noopept facilitated retention and retrieval of a conditioned passive avoidance response, normalized learning capacity in animals with ischemic damage to the cerebral cortex, and promoted finish training in rats with hereditary learning deficit. These results show that Noopept improves all three stages of memory. It should be emphasized that the effect of Noopept was most pronounced in animals with impaired mnesic function.