PROTEINASE, PHOSPHATASE AND GLUCURONIDASE ACTIVITIES IN THE GROWING MANDIBLE AND TEMPOROMANDIBULAR-JOINT OF THE GUINEA-PIG

This study investigated the effect of muscle function and occlusal form on the activity levels of several enzymes present in the mandible or temporomandibular joint of the guinea pig. Restriction of maxillary width and asymmetric function of the mandible was caused in 12 animals at the age of 10 days, as described in the accompanying paper (Isotupa et al. 1992). Tissue samples from six anatomical sites were obtained from the animals sacrificed 4, 8, or 12 weeks after manipulation (4 animals in each group). Six age-matched animals acted as controls. Five samples were from the following sites of the mandible: the condylar cartilage, the lower and upper parts of processus angularis, and the anterior and posterior halves of the condyle neck. A sample was also obtained from fossa mandibularis of the temporal bone. Buffer extracts of powderized samples were studied for acid and alkaline phosphatase, glucuronidase and two types of proteolytic activity. Although the asymmetric manipulation of occlusion caused observable, localized asymmetric growth, the enzyme findings were not consistently asymmetric. Manipulation generally increased all enzyme activities regardless of whether apposition or resorption was involved. The activities of alkaline phosphatase more consistently showed this pattern, and changes in enzyme activities seemed to be sensitive, reflecting cellular or molecular level of growth. The enzyme activities may also reflect a certain type of after-effect of irritation, or a healing period. The inclusion of several types of enzyme determinations is recommended to complete macroscopic measurements. Subsequent chromatographic and electrophoretic studies are also useful.