Investigation into the aetiology of Australian Stringhalt

Summary

In conjunction with Prof Cahill's laboratory we propose to grow plants from seed in pots and harvest leaves and florets at various times following germination. We also plan to grow a set of plants to maturity and then divide into two groups one that is well watered (controls) and one for which water is withheld (droughted) to simulate dry latesummer/drought conditions. We will also compare these studies with seeds acquired from plants where horses grazing these pastures have not developed stringhalt. During the summers of 2009 and 2010 seeds will be collected from paddocks associated with cases of Stringhalt throughout Victoria Chemical analyses wil then be performed on controls, drought simulated plants and harvested samples, in protocols to identify substances with potential for inducing neurotoxicity A variety of procedures drawing on the expertise of the Analytical Chemistry group at Deakin University will be utilised including: Column chromatography HPLC MSTOF spectrometry Any putative neurotoxins are to be identified and further research is anticipated to elaborate causal roles in the peripheral neuropathy resulting in the clinical syndrome of Australian Stringhalt.

Program

Thoroughbred Horses

Research Organisation

The University of Melbourne

Objective Summary

To identify possible neurotoxins associated with H. radicata particularly when the plant is exposed to prolonged dry conditions. The plants studied will be a combination of those germinated in controlled conditions and any field samples associated with Australian Stringhalt (AS). If several toxins are identified, further studies will be performed to ascertain the likelihood of their role in the peripheral neuropathy that characterises AS. This is a pilot project with further work anticipated using tissue culture systems as the next step to identifying neurotoxicity, with putative toxins selected based on chemical similarity to known plantderived neurotixins. This will be accomplished by exposing equine nerve cell cultures to putative toxins from H. radicata, and depending on these results, confirming toxciity by clinical studies using purified toxin.