ABSTRACT

 Background and Aim: Scientific evidence, over the past 50 years has revealed that fluoride allegedly might lead to shortening of the life span, promotion of cancer and various mental disturbances, acceleration of osteoporosis and fracture of hips in old people. Exposure to fluorides can induce inflammatory reactions, cell^�cycle arrest, and apoptosis in animal cell culture, but less is known^�about fluoride effects on heart histology. There are a few reports about the role of sodium fluoride in induction of degenerative changes in myocytes in animal models. The studies conducted so far, had dealt with the long term effects of sodium fluoride on cardiac cells. The^�aim of this study was to evaluate the short term effects of fluorosis on producing histological changes in heart muscles of rats.

 Material and Methods: Fifty six adult young male rats were divided into experimental and control groups (n=7) randomly. Experimental group received 10 and 20mg of sodium fluoride/kg/day subcutaneously for 14 and 28 days respectively. The control animals received the same volume of phosphate buffer/kg/day. Body and heart weights were measured in control and experimental groups. The heart samples were stained as routine and prepared for histological studies. Data analyzed by means of student T- test.

 Results: The results of our study revealed a significant difference in the body and heart weights in the experimental group as compared with those of the control group. In the experimental group myocardium showed degenerative changes after injections on the 14^th and 28^th days. These changes included presence of hyper-chromatic myocytes and small hemorrhages. The myocardium exhibited degenerative myocytes, dissolution of myocyte nuclei, fibrinolysis, and more interstitial cells in the connective tissue. The degree of myocardial damage seemed to be directly proportional to the dosage of fluoride administered (p<0.05). In the control animals, the myocardium showed normal structure without any of the above mentioned changes.

 Conclusion: Sodium fluoride injection in rat induced significant decrease of body and heart weights soon after injection. Histological studies showed degenerative changes of myocardium during this period.