Are 2,3-dimercapto-1-propanesulfonic acid or prussian blue beneficial in acute thallotoxicosis in rats?

Unithiol (2,3-dimercapto-I-propanesulfonic acid, DMPS) and prussian blue (potassium ferric hexacyanoferrate (II), PB), given alone or in combination, were evaluated as antidotes to treat acute thallotoxicosis in male Sprauge-Dawley rats. Animals were poisoned with 20 mg thallium (TI)/ kg bw PO on day 0 using thallous sulfate. On day 1 (24 h later), treatments began and were continued through day 4 as follows: 50 mg PB/kg bw PO, 2/ d; 5 mg DMPS/kg bw IP, 6/d (day 1), 4/d (day 2), 2/d (days 3-4); or the combination. Animals were sacrificed 24 h after the last treatment (day 5), and TI concentrations in kidney, liver, heart, brain, whole blood and feces determined by electrothermal atomic absorption spectroscopy. The relative accumulation of TI was kidney>>heart>liver approximately equal brain. PB limited incorporation of TI in all tissues. DMPS failed to significantly decrease TI in any organ, but significantly decreased TI in whole blood. PB+DMPS treatment significantly decreased the TI content in all organs, but not to a greater extent than PB alone. PB and PB+DMPS treatments significantly increased TI in feces, whereas DMPS alone produced little effect. This study confirms that PB is beneficial in the treatment of acute thallotoxicosis in rats. The failure of DMPS to significantly affect TI in target organs suggests it is not useful in treating TI poisoning.