A recent report has found that
glucose oxidation and the activity of
pyruvate dehydrogenase (PDH) are reduced in the chronic stage of the
pilocarpine mouse
epilepsy model. This is likely caused by increased phosphorylation by
PDH kinase of the E1α subunit of PDH, downregulating its activity. Inhibition of this phosphorylation has not yet been explored as a possible approach to treat
epilepsy. Chronic dichloroacetate (DCA, 50 and 100 mg/kg/day) treatment was tested in acute seizure and the chronic
pilocarpine models. We also determined the effects on phosphorylation state, activity and
protein levels of PDH in the chronic stage of the
pilocarpine model. DCA treatment did not increase latencies to
seizures in the acute
flurothyl seizure test and was slightly proconvulsant in the 6 Hz test. The latencies to
seizures in a second-hit
flurothyl test were decreased in SE vs. No SE mice in the chronic stage, but were not restored by DCA. In mice that had experienced
pilocarpine-induced SE and were in the chronic "epileptic" stage of the model, PDH activity was reduced by 65% compared to "healthy" No SE mice. This was partially alleviated with DCA treatment. Also, PDH
protein levels were decreased by 37% and phosphorylation at Ser300 of PDH was increased by 52% in SE mice, but were not significantly changed with DCA. Moreover DCA treatment decreased the amounts of total PDH by 23% in No SE mice, which may explain the proconvulsant effects in the 6 Hz test. The reduction in PDH
protein levels during the chronic epileptic stage suggests increased degradation of the
protein, which may contribute to the deficient
glucose oxidation found in
epilepsy. Taken together, DCA did not have any anti-
convulsant effects in the tested models. Future studies utilising other
PDH kinase inhibitors are required to determine whether this treatment approach is viable.