A step-by-step approach to minimally photothrombotic ischemic stroke in the hippocampal region that simulates human stroke.

Abstract

The hippocampal structure, characterized by blood vessels with an average diameter of 0.5&#xa0;mm, exhibits a significant vulnerability to ischemic conditions and is the critical region in the learning process and memory establishment. Male mice (n&#x2009;=&#x2009;30) were divided into three groups (each group n&#x2009;=&#x2009;10). 1) Rose Bengal group, 2) Laser group, 3) Rose Bengal&#x2009;+&#x2009;Laser group. Mice were placed in a stereotaxic device. An optical fiber was positioned above the ascending part of the hippocampal fissure and illuminated for 15&#xa0;min using a previously injected intraperitoneal Rose Bengal dye. The Passive avoidance and MWM tests evaluated learning ability and memory capacity. TTC and Cresyl violet staining were conducted to assess the neural tissue morphology and histological alterations. Photochemical stroke resulted in hemorrhagic tissue and pale ischemic changes over three days. Microscopic analysis revealed neural tissue degeneration and disruption in the (Rose Bengal&#x2009;+&#x2009;Laser) group compared to the other experimental groups. The passive avoidance test demonstrated a statistically significant reduction in the time required to reach the dark compartment within the (Rose Bengal&#x2009;+&#x2009;Laser) group relative to the other groups (P&#x2009;<&#x2009;0.001). Furthermore, treatment with Rose Bengal and laser irradiation was associated with a decline in spatial learning and memory, as evidenced by decreased time spent in the target quadrant compared to the other quadrants (P&#x2009;<&#x2009;0.001). Our findings indicate that the application of Rose Bengal alongside laser irradiation results in cellular injury, disruption of neural tissue, and impairment of learning and memory performance.