Evaluation of carcinogenic effect of mineral oil used in the processing of jute fibres.

To evaluate the carcinogenic activity of jute-batching oil (JBO), this substance was painted on the skin of ITRC mice up to 300 days. Initially hyper- and parakeratosis of the stratum corneum, acanthosis and spongiosis of the stratum Malpighii, hyperactivity of fibroblasts, and laying down of collagen fibres in the dermis were encountered at 100 days. This was followed by poor hair growth, acne formation and ulceration. As time passed, these animals partially adapted themselves to the oil-painting so that by 200 days hyperkeratosis and parakeratosis of the stratum corneum, as well as acanthosis and spongiosis of the stratum Malpighii, had almost disappeared. The ulcers healed and no more acne was visible; however, the baldness and loss of hair appendages persisted to 300 days. No carcinogenic changes in the skin or in the viscera of these mice were observed. On UV and IR spectroscopy no traces of any polycyclic aromatic hydrocarbons were found in the JBO sample. Mice, on the other hand, when painted with the known carcinogen 3,4 benzpyrene (BP), developed skin tumours, showing that the mice used in this study were not cancer-resistant. Also, when JBO was applied with BP, the time taken for tumour development in mice was shortened by about 4 weeks as compared to another group painted with the same dose of BP alone. This suggests a cancer-promoting activity which needs to be investigated further.