Korean J Orthod.  1984 Mar;14(1):53-63.

An experimental study on the histopathological change of the mandibular joint by muscle alteration in rat

• Park YC

Abstract

The purpose of this study was to investigate the histopathological change and adaptation process of the mandibular joint of the rat by muscle alteration. For this study, one hunderd and twenty eight rats of 25-and 60-day old of age were used. Unilateral and bilateral detachment, with anterior positioniong of the Masseter muscle, was performed under anesthesia. The animal was sacrified 10, 20, 50, 80 days postoperatively. This alteration in muscle function led to change in meuromuscular activity and demonstrated the adaptive nature of the condyle cartilage to functional demand. The results were as follows: 1. In the right muscle detached group, operated at 25 days of age, marked decrease on the chondroblastic zone was found in the condyle head on the right side of animals examined 10 days postoperatively. Comparing with the control group, no difference was found on the chondroblastic zone in the condylar head of animals examined 20, 50 and 80 days postoperaticely. 2. In the bilateral muscle detached group, operated at 25 days of ate, the chondroblastic zone was slightly dexreased in the anterior parts of condylar head of animals examined 10 days postoperatively. 3. In the unilateral and bilateral muscle detached group, operater at 60 days of age, no significant change was found in the mandibular joint regardless of the post operative experimental periods. 4. Under Toluidine blue staining, slightly decreased metachromasia was found in the condyle head on the right side of unulateral experimental animals, operated at 25 days of age and examined 10 days postoperatively. 5. Under Masson's trichrome staining, increased metachromasia was found in the condyle head on the right side of unilateral experimental animals, operated at 25 days of age and examined 10 days postoperatively. In symmary, the condyle of the rat could respond to changes in neuromuscular activity depend on the level of maturation of the tissue, because the endochondral bone formation of the condyle of the rat was almost ended within 3 months.

MeSH Terms

Anesthesia
Animals
Cartilage
Chondrocytes
Head
Joints*
Masseter Muscle
Osteogenesis
Rats*
Tolonium Chloride
Tolonium Chloride