Rats anticipate damaged rungs on the elevated ladder: Applications for rodent models of Parkinson's disease.

The present study examined rats' ability to anticipate undetectable wider gaps between rungs produced when they stepped on and dislodged damaged rungs while they traversed a slightly inclined elevated ladder. Rats in the first of three experiments reduced running speeds when they encountered four evenly spaced damaged rungs either always placed on the first or second half of the ladder (the break-a-way (BW) phase) but quickly recovered to their baseline (BL) levels when damaged rungs where replaced with intact rungs (the recovery phase). Rats previously exposed to damaged rungs over the first half of the ladder increased their speeds above BL on its second "safer" half during the recovery phase, a delayed "relief-like" positive contrast effect. In Experiment 2, other rats decreased their speeds more as they approached a single damaged rung at a fixed location when it occurred before than after the mid-point of the ladder. Although they quickly recovered to BL speeds on the portion of the ladder after the damaged rung or replaced intact rung, they never showed any "relief-like"/escape effects. Rats also reduced their likelihood of dislodging the damaged rung with a fore paw over extended BW training. In the third experiment rats encountered a more easily dislodged damaged rung that was signaled by a closer intact rung on half the trials. Under these conditions rats displayed a more reliable positive contrast "relief-like" effect. We discussed how traditional associative and cognitive theories of aversive conditioning account for these findings and their relationship to normal changes in dopamine production and possible effects of reduced production from the substantia nigra pars compacta (SNpc) in the Basal ganglia in rodent models of Parkinson's disease.

Genetic susceptibility model of Parkinson's disease resulting from exposure of DJ-1 deficient mice to MPTP: evaluation of neuroprotection by Ubisol-Q10.

INTRODUCTION: Parkinson's disease arises from a combination of environmental and genetic risk factors. At present neither the curative nor preventative therapies are available; hence, there is an urgent need to develop reliable animal models to facilitate their development. Water soluble nanomiceller formulation of CoQ10 (Ubisol-Q10) has shown neuroprotection against neurotoxin on human neuronal cells. We have combined the genetic deficiency of DJ-1/PARK7 mice with MPTP exposure and develop a genetic susceptibility model of PD and evaluated the neuroprotective efficacy of (Ubisol-Q10). METHODS: Transgenic mice with DJ-1 deficiency (DJ-1/PARK7) were given either water or Ubisol-Q10 prophylactically at a dose of 6 mg/kg/day added directly to a drinking water for one month followed challenged with MPTP injections while keeping the same drinking water regiments. Four weeks after the last injection we evaluated neuroprotective efficacy of Ubisol-Q10 in DJ-1/MPTP model of PD using histochemical and behavioral readouts. RESULTS: We confirmed genetic susceptibility to MPTP and showed that prophylactic oral treatment with Ubisol-Q10 significantly offset the neurotoxicity and ameliorated motor dysfunction, otherwise correlated with the MPTP injury. CONCLUSION: Ubisol-Q10 protects against MPTP-induced neurodegeneration and motor dysfunction in DJ-1 deficient mice. Ubisol-Q10 might be a treatment prospect for people genetically predisposed to PD as well as with sporadic PD.

Orally delivered water soluble Coenzyme Q10 (Ubisol-Q10) blocks on-going neurodegeneration in rats exposed to paraquat: potential for therapeutic application in Parkinson's disease.

BACKGROUND: Paraquat, still used as an herbicide in some parts of the world, is now regarded as a dangerous environmental neurotoxin and is linked to the development Parkinson's disease (PD). Paraquat interacts with cellular redox systems and causes mitochondrial dysfunction and the formation of reactive oxygen species, which in turn, plays a crucial role in the pathophysiology of PD. Various antioxidant therapies have been explored with the expectations that they deliver health benefits to the PD patients, however, no such therapies were effective. Here we have tested the neuroprotective efficacy of a novel water-soluble CoQ10 (Ubisol-Q10), in a rat model of paraquat-induced neurodegeneration in order to evaluate its potential application in the management of PD. RESULTS: We have developed a rat model of progressive nigrostriatal degeneration by giving rats five intraperitoneal injections of paraquat (10 mg/kg/injection), once every five days. Neuronal death occurred over a period of 8 weeks with close to 50% reduction in the number of tyrosine hydroxylase-positive cells. Ubisol-Q10, at 6 mg CoQ10/kg body weight/day, was delivered as a supplement in drinking water. The intervention begun after the completion of paraquat injections when the neurodegenerative process had already began and about 20% of TH-positive neurons were lost. Ubisol-Q10 treatment halted the progression of neurodegeneration and remaining neurons were protected. The outcomes were evaluated based on the number of surviving tyrosine hydroxylase-positive neurons in the substantia nigra region and improved motor skills in response to the Ubisol-Q10 intervention. To maintain this neuroprotection, however, continuous Ubisol- Q10 supplementation was required, if withdrawn, the neuronal death pathway resumed, suggesting that the presence of CoQ10 was essential for blocking the pathway. CONCLUSION: The CoQ10, given orally as Ubisol-Q10 in drinking solution, was effective in blocking the progression of neurodegeneration when administered therapeutically (post-toxin injection), at a much lower concentration than other previously tested oil soluble formulations and well within the acceptable daily intake of 12 mg/kg/day. Such unprecedented neuroprotection has never been reported before. These results are very encouraging and suggest that Ubisol-Q10 should be further tested and developed as a therapy for halting the progression of PD.