Therapeutic potential of porphyran in mitigating ischemia-reperfusion injury in gerbil hippocampus.

Abstract

Cerebral ischemia-reperfusion (IR) injury is a critical pathological event that leads to extensive neuronal loss, neuroinflammation, and blood-brain barrier (BBB) dysfunction. Porphyran, a sulfated polysaccharide derived from Porphyra spp., has demonstrated anti-inflammatory and neuroprotective effects in various neurological conditions. This study aimed to evaluate the post-ischemic therapeutic potential of porphyran in a gerbil model of transient forebrain ischemia. Our findings reveal that porphyran administration (50 mg/kg orally once daily for five days) following IR significantly mitigated IR-induced cognitive decline, as evidenced by the Y-maze test, but porphyran treatment did not significantly prevent neuronal death in the CA1 subregion of the hippocampus, as revealed by Cresyl Violet (CV) and Fluoro-Jade B (FJB) staining. However, porphyran treatment after IR injury effectively attenuated the IR-induced decrease in acetylcholine (ACh) levels, suggesting potential preservation of cognitive function in surviving neurons. Furthermore, porphyran significantly mitigated microglial activation and reduced the levels of proinflammatory cytokines (IL-1β, IL-6, and TNF-α), indicating its anti-inflammatory properties. Additionally, porphyran administration reduced BBB disruption, as evidenced by decreased extravasation of immunoglobulin G (IgG), suggesting a role in maintaining vascular integrity. In summary, although porphyrin administration after IR does not protect pyramidal neurons directly, it may improve cognitive function by mitigating ACh depletion, suppressing microglial activation, and reducing inflammatory cytokine levels.