A proline derivative-enriched fraction from Sideroxylon obtusifolium protects against intracerebroventricular pilocarpine-induced injury associated with status epilepticus in mice

The N-methyl-(2S,4R)-trans-4-hydroxy-L-proline-enriched fraction (NMP) from
Sideroxylon obtusifolium was evaluated as a neuroprotective agent in the intracerebroventricular (icv)
pilocarpine (Pilo) model. To this aim, male mice were subdivided into sham (SO, vehicle), Pilo (300
μg/1 μL icv, followed by the vehicle per os, po) and NMP-treated groups (Pilo 300 μg/1 μL icv,
followed by 100 or 200 mg/kg po). The treatments started one day after the Pilo injection and
continued for 15 days. The effects of NMP were assessed by characterizing the preservation of
cognitive function in both the Y-maze and object recognition tests. The hippocampal cell viability
was evaluated by Nissl staining. Additional markers of damage were studied—the glial fibrillary
acidic protein (GFAP) and the ionized calcium-binding adaptor molecule 1 (Iba-1) expression using,
respectively, immunofluorescence and western blot analyses. We also performed molecular docking
experiments revealing that NMP binds to the γ-aminobutyric acid (GABA) transporter 1 (GAT1).
GAT1 expression in the hippocampus was also characterized. Pilo induced cognitive deficits, cell
damage, increased GFAP, Iba-1, and GAT1 expression in the hippocampus. These alterations were
prevented, especially by the higher NMP dose. These data highlight NMP as a promising candidate
for the protection of the hippocampus, as shown by the icv Pilo model.