Effect of diet hardness on mandibular condylar cartilage metabolism.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
diet hardness | no change | ratio of MMP-3 and TIMP-1 immunopositive cartilage cells | female Sprague Dawley rats | - | similar in all age groups | #1 |
- | decrease | number of MMP-8 positive cells | female Sprague Dawley rats | - | decreased with age | #2 |
change of diet from soft to hard | decrease | number of MMP-3 and MMP-8 positive cells | female Sprague Dawley rats | - | caused a significant decrease | #3 |
change of diet from soft to hard | increase | TIMP-1 positive cells | female Sprague Dawley rats | - | an increase | #4 |
diet hardness | neutral | cartilage thickness | female Sprague Dawley rats | - | significantly affected | #5 |
diet hardness | neutral | area of type II collagen-positive staining | female Sprague Dawley rats | - | significantly affected | #6 |
soft diet during growth | increase | collagenolytic activity | - | - | increases | #7 |
soft diet during growth | increase | vulnerability of condylar cartilage | - | - | may increase | #8 |
AIMS: To study the effect of diet hardness on condylar cartilage thickness, extracellular matrix composition, and expression of matrix metalloproteinase (MMP) -3, -8 and tissue inhibitor of metalloproteinase-1 (TIMP-1), by using immunohistochemical and morphometric methods. METHODS: Seventy-two female Sprague Dawley rats were exposed to different dietary hardness, from soft to hard. MMP -3, -8, and TIMP-1 expression, cartilage thickness, cell count, and expression of type II collagen were studied. Analysis of variance among treatments was carried out followed by Bonferroni's comparisons test. RESULTS: The ratio of MMP-3 and TIMP-1 immunopositive cartilage cells were similar in all age groups, whereas the number of MMP-8 positive cells decreased with age. A change of diet from soft to hard caused a significant decrease in the number of MMP-3 and MMP-8 and an increase in TIMP-1 positive cells. Cartilage thickness and area of type II collagen-positive staining were significantly affected by diet hardness. CONCLUSION: The results show that a soft diet during growth increases collagenolytic activity and may increase the vulnerability of condylar cartilage.