INTRODUCTION: Studies concerning exposure of human to lead during daily activities are sometimes leading to many complications. Lead is a poisonous heavy metal, it's toxicity can change the antioxidant balance in biological tissues. Honey is rich in phenolic acids and flavonoids, which exhibit a wide range of biological effects and act as natural antioxidants.
OBJECTIVES: (1) To investigate the histological changes in lingual papillae following lead toxicity in experimental rats. (2) To assess the possible protective effects of honey using scanning electron microscopy (SEM).
MATERIALS AND METHODS: Thirty two adult male albino rats were divided into four groups, eight rats/ group. Group I (control): 1ml distilled water. Group II (control + honey): 50 mg/kg honey + 1ml distilled water. Group III (lead): 16.5 mg lead acetate. Group IV (honey + lead): 16.5 mg lead acetate + 50 mg/kg honey. All doses were given by oral intubations daily /6 weeks. After 6 weeks, rats were sacrificed, and tongues were dissected out and processed for SEM.
RESULTS: In Group II: Increased papillary density of the filiform papillae was noticed. In Group III the filiform papillae were distorted. Some appeared shorter while others had eroded tips and hyperkeratosis. Complete loss of papillae were seen in some samples. Disfigured fungiform papillae with swollen taste buds were seen. In Group IV, filiform and fungiform papillae appeared close to normal with minimal changes.
CONCLUSIONS: The atrophy observed in Group III could be explained by lead-induced oxidative stress. Lead toxicity had a dual effect where increased free radical formation together with depletion of endogenous antioxidant enzymes resulted in inflammation and increased cell injury. Lead causes anemia and decreased salivary secretion, which may explain the epithelial erosion. Honey exerted its protective role through restoring enzymatic activity and through its antioxidant mechanism.