MORPHOLOGICAL AND BIOCHEMICAL-STUDIES OF THE ELASTIC FIBERS IN THE CRANIOMANDIBULAR JOINT ARTICULAR DISC OF THE TIGHT-SKIN MOUSE

The tight-skin (TSK) mouse is characterized by the hyperplasia of loos e connective tissues, and of excessive growth of cartilage and of bone s including the mandible. Since the fibroelastic connective tissues of the craniomandibular joint (CMJ) are essential to the functions of th is joint, the present histological study compared the presence and gen eral distribution of blastic fibres in CMJ discal tissues of TSK and n ormal mice. The excised CMJs were processed for light microscopy. The tissues were fixed, demineralized, embedded in paraffin, sectioned and then stained with resorcin-fuchsin to demonstrate elastic fibers. The re were no obvious histological differences in either the amount or th e distribution of elastic fibres in the discs from the two groups. In both groups, elastic fibres were found in the disc and in many of the attachments of the disc to the mandible and squamosal bone. In additio n to the morphological preparations, articular discs and samples of lu ng tissue were excised from other mice and subjected to a radioimmunoa ssay for desmosine in order to estimate the amounts of elastin in thes e tissues; the amount of elastin was significantly reduced in the TSK lung, but the amounts of elastin in the TSK and normal CMJ discal tiss ues were not significantly different statistically. These morphologica l and histochemical results suggest that the distribution and quantity of elastic fibres in the TSK mouse disc are not significantly differe nt from those in the normal mouse articular disc. Moreover, these data may be interpreted to either suggest a differential effect on the ela stic fibres in different TSK tissues, or to support the suggestion tha t abnormal degradation of elastic fibres may not be characteristic of the TSK mouse. Copyright (C) 1996 Elsevier Science Ltd.