Scanning electron microscopy of dimethylbenzanthracene (DMBA)-treated hamster cheek pouch

Influence of beta-carotene on lysosomal hydrolases and their natural substrates in major salivary glands of hamsters treated with 7,12-dimethylbenzanthracene (DMBA)

We evaluated the effects of beta-carotene, a precursor of vitamin A, on the activity of some lysosomal hydrolases and on the levels of their natural substrates in hamster major salivary glands during experimental oral 7,12-dimethylbenzanthracene (DMBA) carcinogenesis. Sixty-four hamsters (Cricetus auratus) were divided into four groups--group 1: untreated control; group 2: DMBA was painted three times a week in the left buccal pouch; group 3: beta-carotene was painted three times a week in the left buccal pouch; group 4: DMBA and beta-carotene were painted alternatively in the left buccal pouch. After 16 weeks, the animals were sacrificed and the activities of some lysosomal hydrolases and their natural substrates in the major salivary glands were measured. beta-Carotene when administered topically in DMBA treated animals (group 4) reduced the levels of the majority of enzymes and substrates closer to those of the untreated control group, thus outlining a mild protective effect of beta-carotene towards the DMBA carcinogenic stress. Nevertheless, the presence of some enzymes which responded negatively to the combined administration of DMBA and beta-carotene suggests the necessity for future studies on the effect of beta-carotene at different concentrations, the systemic administration and the possibility to combine the topical beta-carotene administration with other chemopreventive drugs.

Lysosomal glycosidases and their natural substrates in major salivary glands of hamsters treated with 7,12-dimethylbenzanthracene (DMBA)

Oro-maxillofacial diseases may influence structure and function of salivary glands. In this study, 32 hamsters were treated with topical application of 7,12-dimethylbenzanthracene (DMBA) on the buccal pouch. After 16 weeks, the animals were killed and the major salivary glands extracted. The activities of some lysosomal glycosidases and their natural substrates were measured to understand how the carcinogenetic stress and the inflammatory reaction could influence the physiology of the salivary glands. Large differences were observed in lysosomal activities among treated and untreated animals. Similarly, large differences were shown in the concentration of natural substrates, including sialic acids. These results suggest that inflammation and/or tumors induce profound changes in the biology of the salivary glands.