Effect of lithium administration on collagen and breaking pressure of the rat thoracic descending aorta

Lithium is widely used in medicine as an antidepressive drug. Despite abundant literature on the subject, questions on the effects of lithium on collagen, which is one of the major components of tissues and organs, are far from being answered. We have examined the effects of lithium chloride (1.5 mEq Li/kg of body weight) on rat thoracic descending aorta: 1) on collagen fibrils by electron microscopy and image analysis and 2) on breaking pressure. Animals were sacrificed 1 day, 2, and 12 months after the end of a 30 consecutive days experimental period. In all cases investigated, structural abnormalities in collagen fibrils, at the ultrastructural level, were found. These abnormalities consist of decreased mean diameter and high variability in width as well as marked disorganization in the packing of the fibrils. The observed alterations seem to be permanent. Rupture of the rat thoracic aorta following pressure is significantly influenced by lithium. (C) 2004 Wiley-Liss. Inc.