| Research Abstract |
We conducted an in vivo experiment to clarify certain relation of inflammation and tongue carcinogenesis. Male F344 rats (4 weeks of age) were given 4-nitroquinoline 1-oxide (4-NQO, 20 ppm) in their drinking water for 8 weeks, and then they were untreated up to 32 experimental weeks. At sacrifice, tongues of all animals were removed and histopathologically examined. Also, IL-α, IL-β, and the densities of mast cells and microvessels were assayed in the stroma of various tongue lesions including non-lesional areas, hyperplastic lesions, dysplastic lesions, and squamous cell carcinomas. The measurements are as follows : IL-α (pg/mg), 7.8±1.5 in the non-lesional areas 13.8±4.6 the hyperplastic lesions, 37.8±7.9 in the dysplastic lesion, 45.1±7.7 in the squamous cell carcinomas ; IL-β (pg/mg), 0.81±0.18 in the non-lesional areas 1.43±0.48 in the hyperplastic lesions, 3.92±0.59 in the dysplastic lesions. 4.62±0.61 in the squamous cell carcinomas ; density of the tryptase-positive mast cell (
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/mm^2), 6.5±1.6 in the non-lesional areas, 9.9±2.0 in the hyperplastic lesions, 18.4±2.0 in the dysplastic lesions, 28.4±5.2 in the squamous cell carcinomas ; density of the CD31-positive neogenesis microvessel (/mm^2), 18.0±1.8 in the non-lesional areas, 17.8±4.6 in the hyperplastic lesions, 28.4±5.8 in the dysplastic lesions, 51.8±7.2 in the squamous cell carcinomas. All the values significantly increased with development of tongue carcinogenesis process (P <0.05). These results may indicate that inflammation was associated with development of tongue carcinogenesis, particularly malignant conversion. In addition, the correlation of the increase in the density of the mast cell and angiogenesis were suggested. In particular, an increase in mast cell density was observed in the front of cancer invasion.
Our findings may suggest that inflammatory mast cell mobilized in the preneoplastic lesions and front of the cancer invasion reorganize their stroma in order to promote angiogenesis. We are now analyzing relationship between PPARs' expression and angiogenetic using samples obtained in this experiment in order to establish a novel strategy of chemoprevention against tongue cancer development. Less
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