Switching to normal diet reverses kwashiorkor-induced salivary impairments via increased nitric oxide level and expression of aquaporin 5 in the submandibular glands of male Wistar rats.

Kwashiorkor, a form of malnutrition has been shown to cause impaired salivary secretion. However, there is dearth of information on mechanism that underlies this complication. Also, whether returning to normal-diet after kwashiorkor will reverse these complications or not is yet to be discerned. Thus, this study aimed at assessing the mechanisms that underlie kwashiorkor-induced salivary impairments and to evaluate the effects of switching back to normal-diet on kwashiorkor-induced salivary impairments. Weaning rats were randomly divided into 3 groups (control, kwashiorkor, re-fed kwashiorkor) of 7 rats each. The control had standard rat-chow while the kwashiorkor group (KG) and re-fed kwashiorkor group (RKG) were fed 2% protein-diet for 6 weeks to induce kwashiorkor. The RKG had their diet changed to standard rat-chow for another 6 weeks. Blood and stimulated saliva samples were collected for the analysis of total protein, electrolytes, amylase, IgA secretion rate, leptin and ghrelin. Tissue total protein, nitric oxide level, expressions of Na+/K+-ATPase, muscarinic (M3) receptor and aquaporin5 in the submandibular glands were also determined. Data were presented as mean ± SEM and compared using ANOVA with Tukey's post-hoc test. RKG showed improved salivary function evidenced by reduced salivary lag-time, potassium, with increased, flow rate, sodium, amylase, IgA secretion rate, leptin, submandibular nitric oxide level and aquaporin5 expression compared with KG. This study for the first time has demonstrated that kwashiorkor caused significant reduction in salivary secretion through reduction of nitric oxide level and aquaporin5 expression in submandibular salivary glands. Normal-diet re-feeding after kwashiorkor returned salivary secretion to normal.