Effects of lathyrogens on the mechanical strength of the periodontal ligament in the rat mandibular first molar

Abstract

Effects of lathyrogens such as aminoacetonitrile (AAN), beta-aminopropionitrile (BAPN) and cysteamine--known inhibitors of cross-linking of collagen--on the mechanical strength of the periodontal ligament of the rat mandibular first molar were examined by measuring the ultimate load required to extract the tooth from its socket in the dissected jaw. Single injections of AAN (40 approximately 100 mg/100 g body weight) or of BAPN (100 mg/100 g body weight) caused significant decreases of the mechanical strength 24 h after administration of the drugs but that of cysteamine (30 mg/100 g body weight) did not. Significant correlations between the dose of AAN or of BAPN and the mechanical strength were found following daily administrations of the drugs for 5 days. The relative potency of AAN to BAPN was estimated to be 4.5 by a slope ratio assay. The rapid appearance and disappearance of the effect of lathyrogens on the mechanical strength of the periodontal ligament of the rat mandibular first molar provide further evidence that the turnover of the collagen in the tissue is fast. The half-time of collagen synthesis was estimated to be approximately 3 d.

The Effect of Age on the Mechanical Properties of the Periodontal Ligament in the Incisor Teeth of Growing Young Rats1

“…A close correlation has also been found between the mechanical properties and the content of insoluble collagens [Vogel, 1975[Vogel, , 1978. This has been proved by the fact that lathyrogens, which interfere with the cross-linking of collagen, diminish the mechanical strength of various connective tissues such as skin [Fry et al, 1962], bones [Vogel, 1975], aorta [Fry et al,, 1962;Lykkeet al, 1960], and periodontal ligament of the rat incisor [Ohshima, 1982], In addition, it has been suggested that the pattern of cross-linking of collagen [Moriguchi & Fujimoto, 1978] and the diameter of constituent collagen fibrils [Parry, 1988;Parry et al, 1978] closely correlated with the mechanical strength of connective tissues. Changes of most mechanical parameters at high extension during maturation was explained by an increase in the cross-linking of collagen [Vogel, 1980].…”

“…It has been demonstrated that the ultimate load required to extract a rat incisor from its socket increased gradually with age from 4 to 24 weeks [Chiba et al, 1980]. It has also been shown that factors such as occlusion and certain types of drugs affect the ultimate load required to extract a tooth from its socket [Chiba et al, 1981a, b;Ohshima, 1982].…”

Local effects of impaired mechanical properties of collagen on bone formation and resorption

“…A reduction in mechanical strength of PDL fibres following lathyrogen treatment of rats has been previously demonstrated (Moxham and Berkovitz 1984;Ohshima et al 1989). It is quite possible that the reduction in bone resorption parameters is caused by the inhibition of PGE2 synthesis due to the reduced tensile strength of collagen in response to B-APN treatment.…”

“…The collagen Type-I is a major constituent of the bone and the periodontal ligament (Rao et al 1979;Veis and Sabsay 1987). It is known that B-APN can cause the reduction of mechanical strength in bone and periodontal ligament via inhibition of the tensile strength of collagen (Ohshima et al 1989;Spengler et al 1977). B-APN is known to cause an impairment of the rate of eruption of the rat incisor (Berkovitz et al 1972;Michaeli et al 1975).…”

Mechanical Properties of the Periodontal Ligament in the Incisor Teeth of Rats from 6 to 24 Months of Age

“…However, this does not necessarily mean that the periodontal ligament of the rat incisor is a stable tissue. In fact, it has been shown that the periodontal ligament responds very sensitively to various internal and external factors such as drugs [Chiba et al, 1981;Ohshima, 1982] and occlusal conditions [Komatsu, 1988]. It is plausible that dynamic changes in the quality and quantity of the ligament are continuously occurring along the long axis of tbe incisor tChiba et al, 1990] throughout the animars life in association with the eruptive movement of the tooth.…”