en Physiology Physiology پژوهشي Research <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Introduction</b>: Propylene glycol (PG) is frequently used as a solvent for various medications. However, there is substantial evidence of Propylene glycol toxicity, such as depression, agitation, and seizures, particularly when used in combination with other drugs. Here, we aimed to study the effect of Propylene glycol administration in combination with amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀ injection on hippocampal neurons.</span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Material & Methods</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: </span></span></b>Thirty-six male Wistar rats were randomly divided into four groups: sham, amyloid &beta;₁<span cambria="" math="" style="font-family:">₋</span>₄₀ injection group, Propylene glycol group, and amyloid &beta;₁<span cambria="" math="" style="font-family:">₋</span>₄₀ + Propylene glycol group. Alternation behavior, number of neurons in the hippocampus, lipid peroxidation markers, and superoxide dismutase levels were analyzed in all rats.</span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Results</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: </span></span></b>When Propylene glycol was co-administered with amyloid &beta;₁<span cambria="" math="" style="font-family:">₋</span>₄₀, a notable reduction in the mean neuronal count was observed in the CA1, CA3, and DG regions compared with the amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀ only injected animals (P < 0.05). Furthermore, Propylene glycol induced an increase in lipid peroxidation markers (10.78 &plusmn; 0.4) and a decrease in antioxidant content (2.8 &plusmn; 0.17) when administered with amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀, compared to the animals that received only amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀ (P < 0.05). A similar pattern was found in alternation behavior compared with the group with amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀ injection (P < 0.001).</span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Conclusion</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: &nbsp;</span></span></b>Propylene glycol could produce excessive neurotoxicity in regions of the hippocampus when co-administered with amyloid &beta;₁<span new="" roman="" style="font-family:" times="">₋</span>₄₀. It likely increases lipid peroxidation and reduces superoxide dismutase in the rat brain. The use of different agents as a vehicle should be considered, especially in the elderly.</span></span><br> &nbsp; Propylene Glycol, Superoxide Dismutase, Malondialdehyde, Neurodegenerative Diseases, Amyloid beta-Peptides 1 11 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-751-3&slc_lang=en&sid=1 Sajjad Salari sajjad.salari@medilam.ac.ir 10031947532846006559 10031947532846006559 No Ilam University of Medical Sciences, Faculty of Medicine, Department of Physiology, Ilam, Iran Maryam Bagheri maryam.bagheri@medilam.ac.ir 10031947532846006560 10031947532846006560 Yes Ilam University of Medical Sciences, Faculty of Medicine, Department of Physiology, Ilam, Iran