Catalog Home Page

Efficacy of oryzalin and associated histological changes in Cryptosporidium-infected neonatal rats

Armson, A., Menon, K., O'Hara, A., MacDonald, L.M., Read, C.M., Sargent, K., Thompson, R.C.A. and Reynoldson, J.A. (2002) Efficacy of oryzalin and associated histological changes in Cryptosporidium-infected neonatal rats. Parasitology, 125 (02). pp. 113-117.

[img]
Preview
PDF - Published Version
Download (215kB) | Preview
    Link to Published Version: http://dx.doi.org/10.1017/S003118200200197X
    *Subscription may be required

    Abstract

    This paper reports the anti-cryptosporidial effects of, and concomitant amelioration of the histological changes in the gut of neonatal rats with intestinal cryptosporidiosis treated with the dinitroaniline, oryzalin. The ED50 was determined to be 7 mg/kg using twice daily doses administered for 3 consecutive days. A maximum inhibition of 85.5% was achieved at 25 mg/kg and this inhibition remained constant despite increasing the oryzalin dose to 200 mg/kg. Cryptosporidiosis significantly decreased the intestinal villus/crypt (VC) ratio by approximately 50% (duodenum = 2.3, jejunum = 2.5 and ileum = 1.7) when compared to uninfected untreated controls (duodenum = 4.3, jejunum = 5.9 and ileum = 4.5). Treatment with oryzalin doubled the VC ratio in the duodenum, jejunum and ileum following doses of 5 mg, 50 mg and 200 mg/kg respectively. Oryzalin concentrations in the small intestine contents and plasma were determined, using HPLC, at 0.5, 1 and 2 h after dosing. The much greater dose required to return VC ratios to normal in the ileum (200 mg/kg) compared to the duodenum (6.25 mg/kg) appeared to reflect the decreased concentration of the drug in the distal small intestine. Concentrations of oryzalin equivalent to the in vitro IC50 were maintained for 2 h in the first half of the small intestine following a single dose of 100 mg/kg.

    Publication Type: Journal Article
    Murdoch Affiliation: School of Veterinary and Biomedical Sciences
    Publisher: Cambridge University Press
    URI: http://researchrepository.murdoch.edu.au/id/eprint/10488
    Item Control Page

    Downloads

    Downloads per month over past year