Abstract
Background: Monosodium glutamate (MSG) toxicity in rodents reportedly causes damage to the brain via oxidative stress. Telfairia occidentalis ethanolic extract (TOE) may mitigate this damage by virtue of its known antioxidant property. This study investigated the possible protective role of TOE against MSGinduced alterations in rat brain microanatomy.
Materials and methods: Forty two adult male rats (130-150 g) were randomized into six groups as follows: Group 1: Control, food and water; Group 2: TOE (400 mg/kg body wt.); Group 3: VIT E (500 mg/kg body wt.); Group 4: MSG (4 g/kg body wt.); Group 5: MSG (4 g/kg) + VIT E (500 mg/kg) and Group 6: MSG (4 g/kg) + TOE (400 mg/kg). MSG was given to induce neurotoxicity in rats one hour before treatment with TOE or VIT E. All treatments were given by gastric gavage for 14 days. Behavioural tests were conducted on day 15 and the rats were subsequently euthanized with i.p. Ketamine hydrochloride. The harvested brain tissues were fixed in neutral buffered formalin and hippocampal biopsies processed for light microscopy using haematoxylin and eosin stain. Granule and pyramidal neurons of hippocampus were assessed quantitatively.
Results: Monosodium glutamate significantly reduced the frequency of some behavioural tests while increasing others relative to control group. MSG induced degeneration of some granule and pyramidal neurons of the hippocampus and also significantly (p<0.05) reduced the neuronal count of both neuron types. Both MSG + VIT E and MSG + TOE co-treatments reversed the histologic alteration and significantly elevated neuronal density when compared with MSG group.
Conclusion: The ethanolic extract of Telfairia occidentalis demonstrated protective effects against MSGinduced histological alterations in rat hippocampus.
Keywords: Monosodium glutamate, Telfairia occidentalis, dentate granule cells, CA3 pyramidal neurons, neurodegeneration.
Résumé
Contexte: La toxicité du glutamate de mono-sodium (GMS) chez les rongeurs cause de manière constatée des dommages au cerveau par le biais du stress oxydatif. L’extrait éthanoïque de
Telfairia occidentalis (ETO) peut atténuer ces dommages en raison de sa propriété antioxydant connue. Cette étude a examiné le rôle protecteur éventuel d’ETO contre les altérations induites par le GMS dans la micro-anatomie du cerveau du rat.
Matériels et méthodes: Quarante-deux rats mâles adultes ( 130-150 g) ont été randomisés en six groupes comme suit: Groupe 1: contrôle, nourriture et eau; Groupe 2 : ETO (400 mg / kg de poids corporel); Groupe 3: VIT E (500 mg / kg poids corporel); Groupe 4: GMS (4 g / kg de poids corporel); Groupe 5: GMS (4 g / kg) + VIT E (500 mg / kg) et groupe 6: GMS (4 g / kg) + TOE (400 mg / kg). On a administré le GMS pour induire une neuro-toxicité chez les rats une heure avant le traitement par ETO ou VIT E. Tous les traitements ont été administrés par gavage gastrique pendant 14 jours. Des tests comportementaux ont été effectués au jour 15 et les rats ont ensuite été euthanasiés avec le chlorhydrate de kétamine i.p. Les tissus cérébraux recueillis ont été fixés dans du formol à tampon neutre et des biopsies de l’hippocampe ont été traitées pour la microscopie optique en utilisant de la coloration à l’ hématoxyline et à l’éosine. Les neurones granulaires et pyramidaux de l’hippocampe ont été évalués quantitativement.
Résultats: Le glutamate mono-sodique a réduit de manière significative la fréquence de certains tests comportementaux tout en en augmentant d’autres par rapport au groupe témoin. Le GMS a induit la dégénérescence de certains neurones granulaires et pyramidaux de l’hippocampe, ainsi qu’a significativement (p <0,05) réduit le nombre de neurones des deux types de neurones. Les deux co-traitements GMS + VIT E et GMS + ETO ont inversé l’altération histologique et ont significativement élevé la densité neuronale par rapport au groupe GMS.
Conclusion: L’extrait éthanoïque de Telfairia occidentalis a démontré des effets protecteurs contre les altérations histologiques induites par le GMS dans l’hippocampe de rat.
Motsclés: Glutamate de mono sodium, Telfairiaoccidentalis, cellules granulaires dentées, neurones pyramidaux CA3,neurodégénérescence Part of this work was presented orally at the 13th National Scientific Conference of the Anatomical Society of Nigeria at Ekiti StateUniversity, Ado-Ekiti, Nigeria, September 19-24, 2016.
Correspondence: Dr. O. Owoeye, Department of Anatomy, College of Health Sciences, Bowen University, Iwo, Nigeria. E-mail: o.owoeye@mail.ui.edu.ng; oowoeye2001@yahoo.com.
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