The levels of neuropeptide S in the brain of asthmatic mice with anxiety and the relationship with the inflammatory mediators

Abstract

Objective: To investigate the levels of neuropeptide S in the brain of asthmatic mice with anxiety and the effects of inflammatory mediatores on changes of neuropeptide S in in vitro experiments. Methods: According to the random number table method, 40 BALB/C mice were randomly divided into 4 groups: the control group, the asthma group, the anxiety group and the asthma and anxiety group. The relative expressions of neuropeptide S mRNA in the brain tissue of each group were detected by quantitative real-time polymerase chain reaction(QRT-PCR). Rat cortex neurons obtained by primary culture were divided into 4 groups: the PBS control group, the interleukin-1 beta group, the interleukin-6 group and the tumor necrosis factor-alpha group. After stimulation with inflammatory cytokines the mRNA expressions of neuropeptide S were measured by QRT-PCR and neuropeptide S levels in the cell culture supernatants were measured by emzyme linked immunosorbent assay(ELISA). Results: The relative expressions of neuropeptide S mRNA were decreased in the anxiety group(0.87±0.05) and the asthma and anxiety group(0.79±0.03)compared with the control group(1.00±0.05)and the asthma group(0.96±0.06), most notably in the asthma and anxiety group (all P<0.05). Compared to the PBS control group[(1.00±0.06), (50.6±1. 8)ng/L] and the interleukin-1 beta group[(0.94±0.08), (49.5±1.0)ng/L], the levels of neuropeptide S mRNA and neuropeptide S were decreased in the interleukin-6 group[(0.88±0.07), (45.4±1.2)ng/L] and the tumor necrosis factor-alpha group[(0.86±0.07), (46.0±1.0)ng/L](all P<0.05). There were no significant differences between the interleukin-1 beta group and the PBS control group(all P>0.05). Conclusions: Up-regulated interleukin-6 and tumor necrosis factor-alpha in asthma can inhibit the secretion of neuropeptide S in neuronal cells. The decline of brain neuropeptide S, which has anti-anxiety effect, may lead to the occurrence of anxiety, which may be a potential mechanism of comorbidity of asthma and anxiety.