Olfactory bulbectomy-induced changes in phospholipids and protein profiles in the hippocampus and prefrontal cortex of rats. A preliminary study using a FTIR spectroscopy

Background: Dysfunctions in neuronal proteins can lead to development of depression. Lipids determine the localization and function of proteins in the cell membrane and thereby regulate synaptic throughput in neurons. The aim of study was to examine changes in the phospholipid-protein balance in the olfactory bulbectomy (OB) model of depression in rats using a Fourier transform infra-red (FTIR) spectroscopy. Methods Sprague Dawley rats were subjected to the OB procedure and treated with amitriptyline (AMI, 10 mg/kg). The FTIR measurements were performed in the hippocampus and prefrontal cortex. Results The obtained results show a decrease in the phospholipids and protein fractions (as well as changes in their secondary structures) in both brain areas of bulbectomized rats. AMI treatment reduced phospholipids' and increased the proteins' brain level, yet did not affect the level of phospholipids or increase the proteins in OB rats. Second derivatives calculated from the FTIR spectra provided information that the proteins (but not phospholipids) in both structures of the OB-AMI rats were normalized after antidepressant treatment. Conclusions Our findings prove that the changes in the phospholipid-protein balance in the hippocampus and prefrontal cortex may be related to depressive disorders, thus leading to the development of adverse changes in the molecules necessary for the correct functioning of the brain. Furthermore, these results suggest a stability of the structure changes/damage of phospholipids in depression, which are present in brain tissues even after effective pharmacotherapy. This study also shows that an infrared spectroscopy can be applied for monitoring changes in mood disorders.