| Popis: |
Schizophrenia is primarily treated with the use of antipsychotic medications. However, antipsychotics used have severe, dose-dependent side effects in schizophrenia patients. Therefore, there is a need for new adjunctive drugs that lower the effective dose of first line schizophrenia drugs and improve patient symptoms. Neuroinflammation is associated with microglial activation in schizophrenia, and increased tumor necrosis factor-alpha (TNF) has shown to be associated with Metabolic Syndrome in schizophrenia patients. A newly developed anti-neuroinflammatory, PD2024, reduces TNF-alpha action in vitro and in vivo, and has been shown to be well-tolerated in rat and dog studies with no adverse effects. The purpose of this research is to evaluate the effect of PD2024 in two well-defined schizophrenia models in rats. The neonatal quinpirole model has been established through administration of the dopamine D2-like agonist quinpirole (NQ) or saline control (NS) postnatally from days 1-21. NQ treatment results in increases of dopamine D2 receptor sensitivity throughout the animal’s lifetime without changing receptor number, mimicking a hallmark of schizophrenia. The polyinosinic:polycytidylic acid (Poly I:C) model is based on mimicking an increase immune response during early brain development, which has been shown to increase the prevalence of schizophrenia. Poly I:C (2 mg/kg) was administered during the neonatal period at postnatal days (P)5-7 to produce this effect. Both models were given PD2024 at 10mg/kg orally through the diet from P30-67. Prepulse inhibition (PPI) was used to test sensorimotor gating deficits in the rats. PPI has past research showing its use as a quantitative phenotype for evaluating schizophrenia-associated behavioral and neurobiological deficits. In our PPI test, rats are exposed to three different, randomly ordered noise trials. The trials included a pulse trial with a 120-decibel startle pulse, a prepulse trial with an auditory click at 73, 76, or 82-decibels, and a no stimulus trial without any additional noise. The rats were given 25 randomized trials, comprised of 5 pulse, 15 prepulse (5 each of 73, 76, and 82dB) and 5 no stimulus trials. Background noise was 70dB, and the rats were tested during adolescence (days 45-46) and adulthood (60-65). In NQ adolescent rats, PPI was significantly improved in the PD2024-treated compared to NQ controls. NQ-PD2024 and NS rats were statistically equivalent throughout the trials. These results were reflected in the NQ adult model as well. The Poly I:C adolescents treated with PD2024 also demonstrated improved PPI performance compared to Poly I:C controls. This improvement was also shown in the adult Poly I:C rats. Overall, the PPI deficits in both models improved between 15 to 30% in adolescence and adulthood. These results indicate that PD2024 is effective in treating schizophrenia-associated behaviors. |
