Tamarindus indica ameliorates behavioral and cytoarchitectural changes in the cerebellar cortex following prenatal aluminum chloride exposure in Wistar rats

Abstract

Aluminium exposure has been linked with developmental neurotoxicity in humans and experimental animals. The study aimed to evaluate the ameliorative effect of Tamarindus indica on the developing cerebellar cortex, neurobehavior, and immunohistochemistry of the cerebellar cortex following prenatal aluminum chloride (AlCl₃) exposure. Pregnant timed Wistar rats were divided into 5 groups (n=4). Group I (negative control) was given distilled water, group II was treated with 200 mg/kg of AlCl₃, group III were given 200 mg/kg of AlCl₃ and 400 mg/kg of ethyl acetate leaf fraction of Tamarindus indica (EATI), group IV were given 200 mg/kg of AlCl₃ and 800 mg/kg of EATI, and group V were treated with 200 mg/kg of AlCl₃ s/c and 300 mg/kg of vitamin E for 14 days (prenatal day 7-21) via the oral route. Male pups (n=6) were randomly selected and taken for neurobehavioral studies, and humanely sacrificed via intraperitoneal injection of thiopental sodium. The cerebellum was removed, fixed and tissue processed for histological and immunohistochemical studies. The results revealed that prenatal AlCl₃ exposure impacted neurodevelopment and neurobehaviour among exposed pups. Prenatal AlCl₃ exposure was marked with delayed cytoarchitectural development of the cerebellar cortex and increased GFAP expression in the cerebellar cortex. On the other hand, treatment with EATI and vitamin E were marked with significant improvements. The present study therefore concluded treatment with EATI shows an ameliorative effect to prenatal AlCl₃ exposure.

Keywords: Aluminum exposure; Glial fibrillary protein; Motor cordination; Tamarindus indica.

Fig. 1

Photmicrograph of the cerebellar cortex on post-natal day 7 from the treatment groups (H&E, ×400). Negative control (distilled water) (A), positive 2 control (200 mg/kg bw of AlCl₃) (B), 200 mg/kg bw of AlCl₃+400 mg/kg bw ethyl acetate leaf fraction of Tamarindus indica (EATI) (C), 200 mg/kg bw of AlCl₃+800 mg/kg bw EATI (D), and 200 mg/kg bw of AlCl₃+300 mg/kg bw of vitamin E (E). EGL, external granular layer; ML, molecular layer; PCL, Purkinje cell layer; IGL, internal granular layer; GC, granular cells.

Fig. 2

Photmicrograph of the cerebellar cortex on post-natal day 21 from the treatment groups (H&E, ×400). Negative control (distilled water) (A), positive 8 control (200 mg/kg bw of AlCl₃) (B), 200 mg/kg bw of AlCl₃+400 mg/kg bw ethyl acetate leaf fraction of Tamarindus indica (EATI) (C), 200 mg/kg bw of AlCl₃+800 mg/kg bw EATI (D), and 200 mg/kg bw of AlCl₃+300 mg/kg bw of vitamin E (E). Red arrow indicates degenerating cells. GL, granular layer; ML: molecular layer; PCL, Purkinje cell 10 layer; PC, Purkinje cell.

Fig. 3

Photmicrograph of the cerebellar cortex on post-natal day 21 from the treatment groups (Cluver 17 berrera; ×400). Negative control (distilled water) (A), positive 14 control (200 mg/kg bw of AlCl₃) (B), 200 mg/kg bw of AlCl₃+400 mg/kg bw ethyl acetate leaf fraction of Tamarindus indica (EATI) (C), 200 mg/kg bw of AlCl₃+800 mg/kg bw EATI 15 (D), and 200 mg/kg bw of AlCl₃+300 mg/kg bw of vitamin E (E). Black arrows indicate dendritic arborization. GL, granular layer; ML, molecular layer; PCL, Purkinje cell 16 layer; PC, Purkinje cell; RLD, region of reduced linear distribution of Purkinje cell.

Fig. 4

Photomicrograph of Wistar rat cerebella cortex on post-natal day 21, showing immune-positive cells (black arrow head) (GFAP, ×400). (A) 2 ml/kg bw of distilled water, (B) 200 mg/kg bw of AlCl₃, (C) 200 mg/kg bw of AlCl₃ and 400 mg/kg bw ethyl acetate leaf fraction of Tamarindus indica (EATI), (D) 200 mg/kg bw of AlCl₃ and 800 mg/kg bw EATI, (E) 200 mg/kg bw of AlCl₃ and 300 mg/kg bw of vitamin E, and (F) the immuno-histochemical score (IHS) using Klein’s semiqualitative approach; with values presented as mean±SEM. ^a,b)Significance difference (P<0.05) compared to the negative control (group 1). GL, granular layer; ML, molecular layer. GFAP is the staining method in this case.