Histomorphological effects of warburgia ugandensis methanolic extract on atherosclerotic lesions in Aortic tunica intima of newzealand rabbits upon Induction of atherosclerosis

Abstract

Atherosclerosis is one of the leading causes of vascular disease worldwide. Its clinical manifestation includes ischemic heart disease, peripheral arterial disease and ischemic stroke. It affects aortic tunica intima manifested by endothelial damage, oxidative stress, inflammation and finally formation of a plaque which eventually harden and narrows the arteries. Warburgia ugandensis a common indigenous plant in East and Central Africa that has been used in treatment of various illnesses and it has been noted to have potential anti-atherosclerotic properties such as anti-inflammatory and anti-oxidant. There is scarcity of information and data in regards to histomorphological effects of W. Ugandensis on atherosclerotic lesions in aortic tunica intima. The current study therefore evaluated the histomorphological effects of Warburgia ugandensis on aortic tunica intima of New Zealand rabbits upon induction of atherosclerosis. Specifically, the study determined acute oral toxicity of W. ugandensis histoinhibitory effects and finally historestorative effects of W. ugandensis on atherosclerotic lesion. In this experimental study, 30 Male pure breed New Zealand rabbits (n=30) weighing 1.8-2kg aged 8-12 weeks sourced from University of Nairobi biology animal house were used as study models. The rabbits were divided into the following study groups: 12 for control ,6 for the experimental and 12 to determine acute oral toxicity. The experimental group was further divided into 2 sub-groups; 3 for histo-inhibitory group, 3 historestorative with W. ugandensis. Induction of atherosclerosis was done using high fat diet for 7 weeks, Later the rabbits were euthanized, tissues harvested and analyzed. One-way Analysis of Variance with post hoc Bonferroni test for continuous data was used to determine difference among and between groups. Flavonoids, Phyto-steroids, tannins, phenols, saponins, alkaloids and anthraquinones were present in methanolic extract while cardiac glycosides were absent. A dose of < 5000mg/kg of W. ugandensis did not have toxic effects. mean fraction of vehicle control significantly increased as compared to negative control group ((p=0.0001). The mean area fraction of histo-inhibitory and historestorative groups significantly reduced as compared to vehicle control group (0.49057,0.37335versus 0.52701). On histological findings; control group, there was a normal tunica intima, well distributed endothelial cells. Vehicle control group; had a fibro-atheroma. On histo-inhibitory groups; had a fatty streak while historestorative groups; had a pre-atheroma with lipid pools. The study concludes that flavonoids, tannins, phenols and Phyto-steroids are present in methanolic bark extract of W. ugandensis and are useful antioxidant and anti-inflammatory components. Safe dose of W. ugandensis in animal study is < 5000mg/kg. W. ugandensis has both histo-inhibitory and historestorative benefits on atherosclerosis. The research therefore, recommends that, quantitative and potency of phytochemical analysis should be carried out to determine the most active molecule in management of atherosclerosis. W. ugandensis bark extract, dose of <5000mg/kg is safe in management of atherosclerosis. Further studies to be conducted to ascertain the drug interactions and effects of W. ugandensis lipid profiles.