Morphological changes and hypoglycemic effects of Annona muricata linn. (annonaceae) leaf aqueous extract on pancreatic β-cells of streptozotocin-treated diabetic rats

Abstract

The present study was undertaken to investigate the leaf aqueous extract effects of Annona muricata Linn. on the morphology of pancreatic β-cells and oxidative stress induced by streptozotocin (STZ)-diabetic rats. Diabetes mellitus was induced in the diabetic animal groups B and C by intraperitoneal injections of STZ (75 mg/kg body
weight), while the control group received equal volume of citrate buffer (pH 6.3) solution intraperitoneally. The rats in group C were given A. muricata leaf aqueous extract (AME, 100 mg/kg, p.o.) as from day 5 post STZ injections, and stopped on the 30th day of the study period. The pancreases of the rats were excised and randomly processed for histological staining and biochemical assays for antioxidant
enzymes [such as glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA) and serum nitric oxide (NO)]. In diabetic state, pancreatic β-cells of STZ-treated group B rats histologically demonstrated marked alterations in the micro-anatomy and cellular integrities. The morphology of A. muricata-treated rats’ pancreases showed viable cellularity with distinct β-cell mass. STZ treatment significantly decreased GSH-Px, SOD, GSH, CAT and pancreatic/serum insulin levels (p<0.05). However, STZ
treatment increased blood glucose concentrations, MDA, and NO. A. muricatatreated rats showed a significant decrease (p<0.05) in elevated blood glucose, MDA and NO. Furthermore, A. muricata treatment significantly increased (p<0.05) antioxidant enzymes’ activities, as well as pancreatic/serum insulin contents. In conclusion, the findings of the present study indicate that A. muricata treatment has
beneficial effects on pancreatic tissues subjected to STZ-induced oxidative stress by directly quenching lipid peroxides and indirectly enhancing production of endogenous antioxidants. Annona muricata protected and preserved pancreatic β- cell integrity. (Afr. J. Biomed. Res. 9: 173 - 180

Keywords: Annona muricata Leaf Aqueous Extract; morphological Changes; Oxidative Stress; Antioxidants.