Neuroinflammation plays a prominent role in the pathophysiology and progression of
schizophrenia. Thus, suppression of
neuroinflammation may retard the progression of the disease. This study was designed to investigate whether
morin, a bioactive compound with
antipsychotic-like activity could reduce
biomarkers of
neuroinflammation and neurodegeneration in
lipopolysaccharide (LPS)- and
ketamine (KET)-induced schizophrenic-like behavior in mice. Animals were treated once daily intraperitoneally with
morin (100 mg/kg),
haloperidol (1 mg/kg),
risperidone (0.5 mg/kg), or saline (10 mL/kg) in combination with LPS (0.1 mg/kg) for 14 consecutive days. However, from days 8-14, overt
schizophrenia-like episode was produced with i.p. injection of KET (20 mg/kg) once daily. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction and social-memory tests) and cognitive (Y-maze test) symptoms were assessed on day 14. Thereafter, the levels and expressions of
biomarkers of
neuroinflammation were estimated in the striatum (ST), prefrontal cortex (PFC) and hippocampus (HC) using spectrophotometry, ELISA and immunohistochemistry. The effects of
morin on cortical pyramidal neurons were estimated using Golgi-impregnation staining technique. LPS in combination with KET significantly (p < 0.05) induced
schizophrenia-like behaviors, which was attenuated by
morin.
Morin significantly (p < 0.05) decreased
tumor necrosis factor-α, interleukine-6 levels and
myeloperoxidase activity in the ST, PFC and HC of mice treated with LPS + KET. Moreover,
morin reduced regional brain expressions of
cyclooxygenase-2,
inducible nitric oxide synthase and
nuclear factor kappa-B, and also rescued loss of pyramidal neurons in the PFC. Taken together, these findings suggest that
morin reduces schizophrenic-like symptoms induced by LPS + KET via mechanisms related to inhibition of the release of pro-inflammatory mediators and suppression of degeneration of cortical pyramidal neurons in mice.