Mitigation of Streptozotocin-induced Cortical Neuronal Loss and Nissl Depletion by Dacryodes edulis Alkaloid Fraction in Adult Wistar Rats
Eru Mba Eru
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Christabel Ojibima Francis *
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Williams Afamuefuna Nnenna
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Michael Effiong Oku
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Eric Agim Agaba
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Charles Effiong Asukwo
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Raymond Asikpo Mbukpa
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Ejiro Ederademu
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Jane-Francis Oluoma Udeh
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
Glory Udochukwu Kings-Nwachukwu
Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Cross River State. Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Diabetes-associated alterations in cortical structure and Nissl substance provide a basis for evaluating the potential protective effects of plant-derived compounds. This study evaluated the potential neuroprotective effect of the alkaloid fraction of Dacryodes edulis on the cytoarchitecture and Nissl substance of STZ-induced diabetic Wistar rats.
Methodology: Twenty-five (25) adult male Wistar rats (130–250 g) were divided into five groups, A–E (n = 5 per group). Group A (control) received rat chow and water. Diabetes was induced in groups B–D by administering 60 mg/kg body weight of streptozotocin (STZ) for 14 days. Groups C and D received 200 mg/kg and 100 mg/kg of alkaloids, respectively, while group E received 50 mg/kg of metformin. The animals were euthanised by intraperitoneal injection of 0.5% ketamine and their brains were excised and fixed in 10% buffered formal saline. The cytoarchitecture of the cerebral cortex was assessed using the haematoxylin and eosin (H&E) staining technique. Nissl substance was assessed histochemically using the cresyl fast violet (CFV) staining technique. Data were analysed using the Statistical Package for the Social Sciences (SPSS), version 25 for Windows. Mean body weight was analysed using one-way ANOVA and Tukey’s test, with P<0.001 considered statistically significant. The duration of the experiment was 56 days.
Results: Group C (STZ + high dose) had the highest percentage change in body weight (32.48%) whereas group D (STZ + low dose) had the lowest (7.12%). Histologically, group A, C and E showed normal neuron with prominent nucleoli while group B and D showed the neuron surrounded by vacuole. Using the cresyl fast violet staining, normal control (group A) was deeply stained, diabetic group (group B) was sparsely stained whereas the treatment groups (C-E) were moderately stained.
Conclusion: The alkaloid fraction of Dacryodes edulis has the potential to ameliorate cortical and nissl depletion from diabetes.
Keywords: Diabetes, alkaloid, streptozotocin, metformin, dacryodes edulis, nissl staining