Impact of cod liver oil supplementation on the histological changes of the tongue dorsal surface in insulin treated streptozotocin induced diabetic rats

Background: Diabetes mellitus (DM) is one of the most common chronic metabolic disease that affecting all age. However, it has many complications such as stomatitis, delayed wound healing, mucosal neuro-sensory disorders. Cod liver oil (CLO) is an important source of ω-3 fatty acids that have anti-inflammatory effect.
Objective: The present study designed to investigate the protective effect of cod liver oil (CLO) supplementation in ameliorating the histological changes of the tongue dorsal surface in streptozotocin (STZ) induced diabetic rats. Design: Forty adult male Swiss albino rats were randomly divided into four groups (n=10). Group (I) rats were received single intraperitoneal injection of 1 ml/kg citrate buffer. Group (II) rats were received single intraperitoneal injection of 60mg/kg STZ freshly dissolved in 1 ml/kg citrate buffer, blood samples were obtained and fasting glycaemia was measured to confirm the development of diabetes. Group (III) after confirmation of diabetes rats were received subcutaneous injection of human insulin with a dose (5 IU/kg/d). Group (IV) rats were treated as in group (III) and received pure cod liver oil with a dose (60mg/Kg /d) by intra-gastric intubation. After four weeks, animals were scarified and tongues were dissected and the prepared sections were examined histologically by H&E, histochemically by Masson Trichrome stain (MTC) and morphomtrical analysis. Data obtained from morphomtrical analysis were statistically described in terms of mean ± standard deviation (± SD).
Results: Histological examination of Group I revealed the normal features of the dorsal surface of tongue and shape of filiform papillae. In Group II has evident hyperkeratosis and loss of conical shape of filiform papillae. Group (III) has better epithelium and keratin layer and shape of filiform papillae. Group IV has histological features resembling nearly those of group I. The morphometric analysis confirmed the previous results as group I showed the highest mean epithelium thickness, followed by Group IV, then Group III and the least value was for Group II.
Conclusions: diabetes has a deleterious effect on dorsal surface of the tongue. Insulin can’t completely inhibit the complications of diabetes. However, ω-3 fatty acids present in CLO has protective effect on these abnormalities caused by diabetes.