Abstract
Citrate may play a role in the transport, mobilization and perhaps deposition of calcium in bone. It is capable of rendering soluble the insoluble calcium salts. Tanner (1967) has observed that citrated rats disclosed severe porosity with alveolar atrophy and myelofibrosis accompanied by bone resorption and hyperemia of the gingiva. This indicated citrates to be directly attributed to loss of alveolar bone and intimately related to advanced alveolar atrophy. This study was designed to confirm the histopathological changes in periodontal tissues in citrated rats and simultaneously to evaluate the calcium and citrate levels in blood. Since it is known that coenzyme Q which is now generally recognized to have an important role in the electron transport system has a profound influence on the citric acid metabolism, the effect of coenzyme Q on the changes in blood and periodontal tissues found in the citrated rats were also studied.
Male albino rats of the Wistar strain, 5 to 7 weeks old and weighing 120-140 gm. were initially fed on powdered normal diet. All animals were given this diet for two weeks before the beginning of the experiment. The animals were then alloted to two groups; one group continuing with the normal diet and another group with the citrate diet which consisted of 10 gm. of sodium citrate and 10 gm. of citric acid homogenized with 80 gm. of powdered normal diet. Both normal and citrated rats were further assigned to subgroups. One subgroup of both groups served as a control. Animals in the second subgroup of both groups were given the diet added coenzyme Q7 powder; each subgroup was fed on normal diet contained 0.005% coenzyme Q7 and citrate diet contained 0.005% coenzyme Q7, respectively. The experimental period lasted three months. At the end of that time the animals were given water but received no food for 15 to 18 hours before the blood was collected. After the blood collection by heart puncture the animals were stunned by a sudden blow on the head and decapitated. The mandibles were fixed to 10% formalin, and then decalcified in a solution of 5% nitric acid and formalin. They were then imbedded in paraffin, and stained with hematoxylin and eosin. The citric acid content of blood was determined by the method of Ettinger et al. (1952) and the serum calcium by the method of Kingsley and Robnett (1957).
In the citrated rats, marked osteoporosis of the alveolar bone and atrophy of the periodontal membrane accompanied by myelofibrosis were observed. These histopathological findings were alleviated by prolonged administration of coenzyme Q. Hypercitricemia with hypercalcemia found in the citrated animals were also restored to the normal level by coenzyme Q administration.
