Background: This study was undertaken to determine changes induced by protein malnutrition (kwashiorkor). in the secretory functions of salivary glands and biochemical parameters of salivary fluid using rats.
Methods: Eighteen male Wistar rats were randomly divided into two groups (control and kwarshiorkor) of 9 rats each. The rats were fed with normal diet and low protein diet (2% protein) respectively for a period of 6 weeks. Stimulated saliva samples using pilocarpine (10 mg/kg body weight i.p.) were collected and salivary glands (parotid and submandibular) were surgically removed. Biochemical analysis of salivary secretion using salivary lag time, flow rate, pH, total protein and concentrations of electrolytes (Na+, K+, Ca++, Cl-, HCO(2-)3 PO4) were conducted and compared. Morphological assessment of the salivary glands was done using heamatoxyline-eosin and Alcian blue stains.
Results: Body weights decreased in the kwashiorkor group. Weights of submandibular and parotid glands (right and left) were lower in the kwashiorkor group compared to the normal diet group. The mean salivary lag time was increased while the salivary flow rate was reduced in the kwashiorkor group compared to normal diet group. Salivary electrolytes and total protein analysis showed reduced concentration of sodium while potassium and bicarbonate concentrations were increased in the kwashiorkor group compared to the normal diet group. Histological analysis of the H-E and alcian blue stained salivary glands in the kwashiorkor group exhibited moderate to severe acinar cell atrophy, periductal fibrosis and reduced mucin content.
Conclusion: These findings suggest the role of functional and biochemical changes in salivary secretion in the pathophysiology of oral diseases associated with protein malnutrition.