Exposure to formaldehyde by injection, ingestion, or inhalation causes toxic effects in the respiratory tract, nervous and urogenital systems and liver as well as inflammation in the brain and kidney in many species including humans. In traditional medicine honeybee products, such as honey, propolis, royal jelly, beeswax, and also bee venom, have long been used as a scavenging agent. The aim of the present study is to evaluate the protective effect of propolis against the hepatotoxic effects of formaldehyde (FA) in rats. 80 adult albino rats (200-250 gm) were divided into four groups. Group 1 was considered as the control group and was treated with water, Group II received propolis (50 mg/kg bw), and Group III received FA (25 mg/kg body weight/day). Group IV received FA (25 mg/kg body weight/day) prior to treatment with propolis (50 mg/kg bw). All rats were administered formaldehyde (FA) and propolis by means of gastric gavage for 2 months. Blood and liver were sampled and prepared for hematological, biochemical, histopathological and ultrastructural examinations. Hematological and histochemical variations detected in Group III were greater in comparison with Groups I & II. Histopathological examination of the liver of rats of Group III showed pyknosis of hepatocyte nuclei, fibrosis, cytoplasmic vacuolation and dilatation of central vein. Ultrastructural examination of the liver of rats of Group III showed damages to the nuclear membrane, with shrinking nucleus and a less prominent nucleolus, swollen and vacuolated mitochondria, large fat droplets, and cytoplasmic vacuoles. The endoplasmic reticuli were small in numbers and enlarged and swollen in shape; also there were degenerated Golgi apparatus and some degenerated hepatocytes. On the other hand, Group IV showed partial and gradual improvement in the pathological changes and the damage of the liver. Our results demonstrate an ameliorative effect of propolis on the FA-induced pathological effects in the liver of rats.
View Full Article