Effects of aflatoxin B1 on the submandibular salivary gland of albino rats and possible therapeutic potential of Rosmarinus officinalis: a light and electron microscopic study

Background: Aflatoxin B1 (AFB1), a highly toxic mycotoxin, is one of the contaminants of food items such as corn, rice, nuts, and flour. This study aimed to evaluate the effect of AFB1 on the histology and ultrastructure of the submandibular salivary glands (SMSG) of albino rats and examine the possible therapeutic effect of Rosmarinus officinalis extract. Methods: This study used 21 adult male albino rats equally divided into three groups as follows: Group C (saline-treated control group); Group A (AFB1 treated group) subjected to intraperitoneal injection of AFB1 (2 mg/kg) once daily for four weeks; Group R (rosemary-treated group) subjected to AFB1 as in Group A followed by two weeks of intraperitoneal injection of Rosmarinus officinalis extract (400mg/kg) once daily. At the end of the experimental periods, SMSGs were excised and fixed for histological and ultrastructural examinations. Results: SMSGs of the AFB1 group presented atrophied serous acini with numerous cytoplasmic vacuolations; their granular convoluted tubules, striated ducts and excretory ducts presented signs of degeneration in their cell lining with the presence of abundant cytoplasmic vacuolations. In addition, dilated blood vessels engorged with red blood cells were frequently seen. Ultrastructural findings of the AFB1 group showed some acinar cells with degenerated mitochondria presenting loss of cristae and vacuolations as well as irregular, shrunken nuclei with condensed chromatin. Dilated rough endoplasmic reticulum were observed in granular convoluted tubules and striated ducts. The glands of animals that received rosemary extract almost regained their normal architecture. Conclusions: It can be concluded that rosemary extract has an ameliorative effect on the deleterious histological and ultrastructural changes induced by chronic AFB1 intake in rat SMSGs.

Keywords: Aflatoxin B1; Antioxidant; Rosemary; Submandibular salivary gland; electron microscope.