Low Serum Levels of Fibroblast Growth Factor 2 in Gunn Rats: A Hyper-bilirubinemia Animal Model of Schizophrenic Symptoms

Background: Fibroblast Growth Factor (FGF) 2 (also referred to as basic FGF) is a multi-functional growth factor that plays a pivotal role in the pro-survival, pro-migration and pro-differentiation of neurons. Method: Because alterations in FGF2 levels are suggested to contribute to the pathogenesis of schizophrenia, we investigated serum levels of FGF2 in the Gunn rat, a hyperbilirubinemia animal model of schizophrenic symptoms. Results: The enzyme-linked immunosorbent assay showed that the serum levels of FGF2 in Gunn rats were 5.09 +/- 0.236 pg/mL, while those in the normal strain Wistar rats, serum levels were 11.90 +/- 2.142 pg/mL. The serum FGF2 levels in Gunn rats were significantly lower than those in Wistar rats. We also measured serum levels of Unconjugated Bilirubin (UCB) and found a significant negative correlation between UCB and FGF2 in terms of serum levels in all the rats studied. Conclusion: Since it is known that FGF2 regulates dopaminergic neurons and have anti-neuroinflammatory effects, our finding suggests that low FGF2 levels may contribute to the pathogenesis of schizophrenia, in which imbalanced dopamin-ergic signaling and neuroinflammation are supposed to play certain roles.