Metabolic depletion of synaptosomal enzymes linked with neurotoxicity and ovarian dysfunction by phenolic antioxidants of Croton zambsicus leaves in rats exposed to chronic mixture of anthropogenic toxicant

Abstract

A complex mixture of organic contaminants and metals is associated with neuron-fertility disorders and studies have demonstrated that phenolic antioxidants from herbal origin, possesses a strong protective potential. This study aimed to investigate the protection of phenolic croton zambesicus (C-ZAMB) leaves against neuro-ovarian damage in rats exposed to chronic mixture of anthropogenic toxicants (EOMABRSL). The animals were divided into five groups (n = 10): Group I was given 0.5 ml of distilled water only; Group II received 0.5 ml of EOMABRSL for 98 days; Group III received 0.5 ml of EOMABRSL for 70 days and withdrew for 28 days; Group IV received 0.5 ml of EOMABRSL for 70 days +400 mg/kg phenolic C-ZAMB for 28 days; Group V received 400 mg/kg C-ZAMB only for 28 days via oral route. Both non-withdrawal and withdrawal EOMABRSL-exposed animals exhibited neuro-ovarian impairment by up-regulating neuronal 5¹ eco-nucleotidase (5¹ENT), acetylcholinesterase (AChE), butrylcholinesterase (BuChE), synaptosomal monoamine oxidase-A (MAO-A) with altered cerebral antioxidants. Similarly, exposure to EOMABRSL for 98 and 70 days caused ovarian injury by amplifying the activity of 5¹ENT with corresponding decline of fertility index, lactate dehydrogenase (LDH) and Δ5 17β-hydroxyl steroid dehydrogenase (Δ517β-HSD). EOMABRSL intoxication also increased the neuro-ovarian MDA content with reduced numbers of neonates. Phenolic antioxidants from C-ZAMB leaves identified by High Pressure Liquid Chromatography (HPLC) ameliorated the chronic EOMABRSL intoxication. The treatment also prevented ovarian lesions by depleting MDA content and improved antioxidant status. Thus, confirming its neuro-ovarian protection.

Keywords: Animal model; Chronic mixture; Metabolic inhibition; Neuro-ovariotoxicity; Phenolic Croton zambesicus; Synaptosome.

Fig. 1

The representative Fourier infra-red chromatography profile of solid sample from the EOMABRSL of Oyo State, Nigeria.

Fig. 2

(a and b): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on malonaldehyde (MDA) content in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 3

(a, b, c and d): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on superoxide dismutase (SOD) and catalase (CAT) activities in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 4

(a, b, c and d): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on glutathione-S-transferase (GST) activity and reduced glutathione (GSH) content in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 5

(a and b): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on lactate dehydrogenase (LDH) activity in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 6

(a and b): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on 5¹ nucleotidase (5¹NT) activity in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 7

Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on hydroxyl steroid dehydrogenase (17-βHSD) activity in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 8

Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on cholinesterase activities (a) AChE and (b) BuChE in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 9

(a and b): Effect of phenolic fraction from Croton zambesicus (C-ZAMB) on mono amine oxidase-A (MAO-A) activities using brain (a) post-mitochondrial fraction (PMF) and (b) synaptosomes in EOMABRSL induced neuro-ovarian damage of rat. Values represent mean ± SD, n = 10; Values with different superscript are significantly (P < 0.05) different.

Fig. 10

Cerebral cortex histopathology changes on rat treated with C-ZAMB in EOMABRSL induced neuro-ovarian damage (original magnification ×400). Control: no visible lesions to the cerebrum or neurons (NVL). NWD-EOMABRSL: The cerebral blood vessels were noticeably overcrowded (CBVNO) WD-EOMABRSL: depicted morphological alterations (MA) when compared with the control. EOMABRSL + C-ZAMB: This group also showed morphological changes (MC) in relation to the control. C-ZAMB only: No visible lesions to the neuronal cells (NVL).

Fig. 11

Ovarian histopathology changes on rat treated with C-ZAMB in EOMABRSL induced neuro-ovarian damage (original magnification ×400). Control: showed adequate numbers of developing ovarian follicles (star) with few congestion of stromal blood vessels (thin arrows). NWD-EOMABRSL: depicted multiple numbers of under-developed ovarian follicles (thick arrow) with remarkable congestion of stroma blood vessels (thin arrow) and large corpora tissue (star). WD-EOMABRSL: There are few under-developing ovarian follicles (thick arrow) with foci of haemorrhages in the ovarian stroma (thin arrows) and large corpora tissue (star). EOMABRSL + C-ZAMB: This showed numerous ovarian follicles (thin arrows) C-ZAMB only: There were mature and developing ovarian follicles (thick arrow) with little congestion of stromal blood vessels (thin arrows).