A biochemical study of the nature of jaw cysts (II). The role of lipids in the enlargement of cysts.

It is believed that cysts in jaws enlarge when the permeability of the cyst wall changes, that the proteins of cyst fluid increase, and that the intracystic fluid pressure on the jaw bone increases because of inflammation. On the other hand, it is also believed that cysts enlarge when a prostaglandin-like substance, which is generated in the wall, acts chemically in the resorption of the jaw bone. This investigation comprised 97 cases of various jaw cysts. The author attempted to treat 91 of these cases by the irrigation method. Lipids and related substances in cyst walls removed at operation in 15 cases, and cyst fluid were examined in all cases as follows. Their identification with IR, analyses of fatty acids with GC, and estimation of the free radical concentration by ESR were carried out. As a result, it was found that in an infected cyst wall the values of phospholipids, TBA and the free radical concentration increased, and that the value of arachidonic acid decreased. In cyst fluid there was no LCAT activity, the value of HDL-cholesterol decreased, and free cholesterol crystals were detected. After irrigation of cyst cavities, cholesterol esters were detected. In infected cyst fluid, the values for white corpuscles, TBA, and the free radical concentration increased, whereas the values of PO2, arachidonic acid, and SOD decreased. As the infection disappeared, these values were reversed. Finally the cysts diminished in size. The author assumes that jaw cyst enlargement is related to LPO and PG-like substances produced by lipid peroxidation of the cyst wall and fluid.