Quantitative analysis of disturbed cell maturation in dysplastic lesions of the respiratory tract epithelium

Abstract

Autoradiographic patterns of [3H]thymidine incorporation, nuclear/cytoplasmic ratios (N/C), and the percentage of dark epithelial cells were analyzed in a group of epithelial lesions induced by 7,12-dimethylbenz[a]anthracene (DMBA) in rat tracheal transplants. It was found that similar lesions of different age exhibit the same labeling indices (LIs), therefore the lesions of different age were subsequently pooled in the following groups and studied by high resolution light microscopic autoradiography: squamous metaplasia without or with only mild atypia, squamous metaplasia with moderate atypia, squamous metaplasia with severe atypia, carcinoma in situ, and microinvasive carcinoma. Normal tracheal and esophageal epithelia were also analyzed. Whereas the normal tracheal basal layer exhibited an LI smaller than 1%, a clear difference between the carcinomas (in situ and invasive) on one hand (LI approximately 32%) and all the remaining epithelia on the other hand (LI approximately 18%) was detected. The LIs of the suprabasal cells exhibited a statistically significant difference between the squamous epithelia without atypia (LI approximately 2%) and the group comprising all the atypical lesions (LI approximately 9%). Gradients of increasing N/C (nucleus-cytoplasm ratios) values could be observed as the lesions increased in severity, especially in the middle and surface layers (e.g., in the surface layer regular metaplasia N/C = 0.08, squamous metaplasia with moderate atypia N/C = 0.26, and carcinoma in situ N/C = 0.50). Dark cells were absent in the normal esophageal epithelium, were present in moderate numbers in the basal layer of regular squamous metaplasia (18%), and increased markedly in the atypical epithelial lesions (approximately 50% in the atypical squamous metaplasias and 70% in carcinoma in situ). In the suprabasal layer dark cells increased from 3% in squamous metaplasia with moderate atypia to 28% in metaplasia with severe atypia and 56% in carcinoma in situ. The results confirm in a quantitative fashion that disturbances of cell maturation and cell proliferation are key features of dysplastic lesions induced by chemical carcinogens, and suggest the use of objective parameters for evaluation and classification of preneoplastic alterations.

VILIP-1 Expression In Vivo Results in Decreased Mouse Skin Keratinocyte Proliferation and Tumor Development

“…VILIP-1 overexpression increases epidermal keratinocyte differentiation in TPA treated skin and this tendency may influence the predominance of well differentiated SCCs in transgenic mice. Decreased cell proliferation could also be an important factor because quite frequently well differentiated SCCs not only have more advanced differentiation patterns than high grade SCCs but are also characterized by a relatively slower cell proliferation [23], [24], [25]. This has also been seen in the tumors, especially in papillomas from transgenic K5-VILIP-1 animals, which showed a significant decrease in Ki67 labeling index with respect to the papillomas from WT mice.…”

Heterotopic tracheal transplants: techniques and applications.

“…Quantitative techniques demonstrated increasing nucleus-cytoplasm ratios, 3H-thymidine labeling indices and number of dark epithelial cells, indicating increasing degrees of cell proliferation and altered cellular maturation (31).…”

Pathological Changes Induced by Formaldehyde in Open-Ended Rat Tracheal Implants Preexposed to Benzo(a)pyrene

“…The two FTTI from each animal were fixed in a 4% formaldehyde-1% glutaraldehyde fixative (9), cut into 8-10 rings and embedded individually in Epon 812. Sections 2 pm thick were prepared for autoradiography as previously described (6). The sections were exposed to Kodak NTB-2 emulsion for 14 days, and stained with toluidine blue or hematoxylin and eosin.…”