Allyl-isothiocyanate ameliorates the pre-neoplastic changes induced by the fern Dryopteris nigropalaceae on experimental feeding in Guinea pigs

Abstract

Enzootic bovine haematuria, caused by long-term ingestion of ferns, is a chronic disease of hill cattle characterized by neoplastic lesions in the urinary bladder. Objectives of this study were to investigate the toxicity potential of long-term feeding of the fern Dryopteris nigropalaceae and effect of allyl isothiocyanate (AITC) to ameliorate fern toxicity and the associated pathological changes. The LC-MS analysis of the fern showed presence of ptaquiloside (4.5 ± 1.0 μg/g) and pterosin B (39 ± 9.1 μg/g). Groups of animals were fed dried fern powder at the dose of 20% w/w in normal feed and treated with and without AITC at graded doses. Long term feeding of fern induced inflammatory and pre-neoplastic lesions in urinary bladder. The important lesions included cystitis, squamous metaplasia and high-grade dysplasia. Urothelium showed positive immunoreactions for nuclear expression of H-ras and p53. However, no mutation suggestive of neoplastic change was observed on partial mRNA sequences analyses of exon 2 of H-ras and 5 or 7&8 of p53 genes. Strikingly, AITC showed dose-dependent amelioration of pre-neoplastic changes in fern-fed animals. In conclusion, AITC is shown to limit pre-neoplastic changes caused by D. nigropalaceae feeding in guinea pigs.