The role of rosemary extract in degeneration of hippocampal neurons induced by kainic acid in the rat: A behavioral and histochemical approach

Article type: Research Article

Authors: Naderali, Elahe^{a; *} | Nikbakht, Farnaz^b | Ofogh, Sattar Norouzi^c | Rasoolijazi, Homa^{a; d; **}

Affiliations: [a] Anatomy Department, Medical school, Iran University of Medical Sciences, Tehran, Iran | [b] Physiology Department, Medical School, Iran University of Medical Sciences, Tehran, Iran | [c] Neuroscience Department, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran | [d] Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran

Correspondence: [**] Corresponding author. Tel.: 0098 21 88622689; Fax: 0098 21 88622689; E-mails: [email protected], [email protected].

Note: [*] Present address: Anatomy Department, Medical school, Tabriz University of Medical Sciences, Tabriz, Iran.

Abstract: Systemic Kainic Acid (KA) administration has been used to induce experimental temporal lobe epilepsy in rats. The aim of this study was to evaluate the neuroprotective effect of rosemary extract (RE, 40% Carnosic acid) against KA-induced neurotoxicity in hippocampus and impaired learning and memory. Animals received a single dose of KA (9.5 mg/kg) intraperitoneally (i.p.) (KA group) and were observed for 2 h and were scored from 0 (for normal, no convulsion) to 5 (for continuous generalized limbic seizures). RE (100 mg/kg, orally) was administered daily for 23 days, starting a week before KA injection (KA+RE group). Neuronal degeneration in hippocampus was demonstrated by using Fluoro-Jade B immunofluorescence. The number of pyramidal cells in hippocampus was evaluated by Nissl staining. Also, the Morris Water Maze and Shuttle box have been used to assess spatial memory and passive avoidance learning, respectively. Our results revealed that, after treatment with RE, neuronal loss in CA1 decreased significantly in the animals in KA+RE group. The Morris water navigation task results revealed that spatial memory impairment decreased in the animals in KA+RE group. Furthermore, results in Shuttle box test showed that passive avoidance learning impairment significantly, upgraded in the animals in KA+RE group. These results suggest that RE may improve the spatial and working memory deficits and also neuronal degeneration induced by toxicity of KA in the rat hippocampus, due to its antioxidant activities.

Keywords: Epilepsy, kainic acid, neurotoxicity, rosemary, learning and memory

DOI: 10.3233/JIN-170035

Journal: Journal of Integrative Neuroscience, vol. 17, no. 1, pp. 31-43, 2018