Roman chamomile inhalation combined with clomipramine treatment improves treatment-resistant depression-like behavior in mice

• Published in: Biomedicine & pharmacotherapy Vol. 118; p. 109263
• Main Authors: Hashikawa-Hobara, Narumi, Otsuka, Ami, Ishikawa, Risa, Hashikawa, Naoya
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01-10-2019; Elsevier
• Subjects: Animals; Behavior, Animal; Cell Proliferation - drug effects; Chamaemelum - chemistry; Chamomile; Chronic stress; Clomipramine - pharmacology; Clomipramine - therapeutic use; Corticosterone; Corticosterone - blood; Cytokines - genetics; Cytokines - metabolism; Depression - blood; Depression - drug therapy; Drug Therapy, Combination; Hippocampus - drug effects; Hippocampus - metabolism; Inhalation Exposure; Male; Mice; Mice, Inbred C57BL; Nerve Growth Factors - genetics; Nerve Growth Factors - metabolism; Neurogenesis - drug effects; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; RNA, Messenger - genetics; RNA, Messenger - metabolism; Stress, Psychological - blood; Stress, Psychological - drug therapy; Treatment-resistant depression; Chronic stress; IL; BDNF; Corticosterone; RT-PCR; Treatment-resistant depression; DCX; Mice; NGF; Chamomile; TNF
• ISSN: 0753-3322; 1950-6007
• DOI: 10.1016/j.biopha.2019.109263

•Chronic stress decreases hippocampal NGF but not cytokine and BDNF mRNA levels.•Roman chamomile with clomipramine decreases immobility time in a forced swim test.•Roman chamomile with clomipramine decreases serum corticosterone levels.•Roman chamomile with clomipramine increases hippocampal neurogenesis.•Roman chamomile with clomipramine may be effective for depression-like behavior.
It is well known that chamomile is one of the oldest known medicinal herbs and has been used to treat various disorders, but it is mainly German chamomile. The effects of Roman chamomile on depression still unclear. In this study, we used chronically stressed mice to investigate whether inhalation of Roman chamomile essential oil affects depression-like behavior. We previously reported that restraint and water immersion stress produce depression-like behavior and a blunted response to the tricyclic antidepressant clomipramine. Each mouse was exposed to restraint and water immersion stress for 15 days, and resistance to the effect of clomipramine was induced in a behavioral despair paradigm. In the present study, we found that cotreatment with clomipramine and inhalation of Roman chamomile attenuated depression-like behavior in a forced swim test. Next, we examined the hippocampal mRNA levels of two cytokines, tumor necrosis factor (TNF) alpha and interleukin-6 (IL-6); a neurotrophic factor, brain derived-neurotrophic factor (BDNF); and nerve growth factor (NGF). TNF alpha, IL-6 and BDNF mRNA levels did not change in the hippocampus of stressed mice. However, the NGF mRNA level was significantly decreased, and this decrease was not attenuated by treatment with clomipramine or inhalation of Roman chamomile alone. We also examined whether Roman chamomile combined with clomipramine treatment affects hippocampal neurogenesis and serum corticosterone levels. Stressed mice had fewer doublecortin (DCX)-positive cells in the subgranular zone of the dentate gyrus, but this was significantly attenuated by Roman chamomile and clomipramine treatment. In addition, the serum corticosterone level was also significantly decreased by treatment with Roman chamomile and clomipramine. These results suggest that Roman chamomile inhalation may enhance the antidepressant effect of clomipramine by increasing hippocampal neurogenesis and modulating corticosterone levels in patients with treatment-resistant depression.