| ObjectiveTo observe the airway inflammation and its effects on mood,learning and memory in the process of asthma modeling in immature rats,and to explore the action mechanism of chiropractic therapy based on the HPA axis.MethodsForty-seven SPF SD rats aged from 3 to 4 weeks were randomly divided into four groups:normal control group,asthma model group,chiropractic intervention group and methylprednisone(MP)intervention group.Except for MP intervention group,each group was randomly divided into sensitization and challenge subgroups.Therefore,the following groups were included as:1)sensitization batch,i.e.,normal control group(n=6),sensitization model group(n=7)and sensitization chiropractic group(n=7);2)challenge batch,i.e.,normal control group(n=6),challenge model group(n=7),challenge chiropractic group(n=7)and challenge MP group(n=7).Asthma model was induced by ovalbumin(OVA)sensitization and challenge,the process of which were also intervened by chiropractic therapy and MP injection.Elevated plus maze and water maze test were carry out to detected the state of anxiety and the ability of learning and memory.Enhanced pause(penh)in awake state were detected to evaluate the respiratory function.Hematoxylin-eosin staining was used to evaluate the lung histopathology.Plasma immunoglobulin E(IgE)level,interleukin-4(IL-4),interferon-y(IFN-γ)and tumor necrosis factor-α(TNF-α)levels in bronchoalveolar lavage fluid(BALF)were detected by enzyme linked immunosorbent assay(ELISA)to evaluate the allergic inflammations.Real-time polymerase chain reaction(PCR)was used to detect the expressions of glucocorticoid receptor(GR)mRNA in the lung tissues,corticotropin releasing hormone(CRH)mRNA in hypothalamus and GR mRNA in the lungs and hippocampus.Plasma adrenocorticotropic hormone(ACTH)and corticosterone(CORT)levels were detected by ELISA to evaluate Hypothalamic-Pituitary-Adrenal(HPA)axis function.All experiments above were done to observe the airway inflammation induced by OVA sensitization and challenge and its impact on behavioral cognition in immature rats,and to explore the HPA-axis mechanism of chiropractic therapy on prevent and treat asthma..Result(1)Compared with the normal control group:the open-arm entries and the percentage of open-arm entries of sensitization model group were significantly reduced in elevated plus maze(P<0.01,P<0.01);in platform quadrant of space exploration experiment in water maze test,the escape latency of orientation navigation experiment and the number of crossings were not significantly different(P>0.05,P>0.05);the lung histopathology score(HPS),plasma IgE level,IL-4 and TNF-α level in BALF were significantly increased(P<0.01,P<0.05,P<0.01,P<0.05);IFN-y level in BALF was not significantly different(P>0.05);plasma ACTH and CORT level were significantly increased(P<0.05,P<0.01);expression of CRH mRNA in the hypothalamus was significantly increased(P<0.01)and GR mRNA in the hippocampus was significantly reduced(P<0.05);expression of GR mRNA in the lung tissues was not significantly different(P>0.05).(2)Compared with the sensitization model group:the open-arm entries and the percentage of open-arm entries of sensitization chiropractic group were significantly increased in elevated plus maze(P<0.01,P<0.05);but not significantly different compared with the normal control group(P>0.05,P>0.05);in platform quadrant of space exploration experiment in water maze test,the escape latency of orientation navigation experiment and the number of crossings were not significantly different(P>0.05,P>0.05);the lung HPS was on a downward trend but not significantly different(P>0.05),IL-4 level in BALF was significantly reduced(P<0.05),IFN-y level in BALF was on a upward trend but not significantly different(P>0.05);plasma IgE level and TNF-α level in BALF were on a downward trend but not significantly different(P>0.05,P>0.05);and not significantly different either compared with the normal control group(P>0.05,P>0.05);plasma ACTH and CORT level and expression of CRH mRNA in hypothalamus were significantly reduced(P<0.05,P<0.05,P<0.05);expression of GR mRNA in hippocampal was on a upward trend but not significantly different(P>0.05);and not significantly different either compared with the normal control group(P>0.05);expression of GR mRNA in the lung tissues was significantly increased(P<0.05).(3)Compared with the normal control group:the open-arm entries and the percentage of open-arm entries of challenge model group were not significantly different(P>0.05,P>0.05);the escape latency of orientation navigation experiment was longer but not significantly different(P>0.05);and the number of crossings in platform quadrant of space exploration experiment on a downward trend but not significantly different(P>0.05);the Penh were markedly enhanced when challenged by two high concentration of Ach(P<0.05,P<0.001);the lung HPS,Plasma IgE level,IL-4 and TNF-α level in BALF were significantly increased(P<0.001,P<0.01,P<0.001,P<0.001);IFN-y level in BALF was significantly reduced(P<0.05);plasma ACTH and CORT level were on a downward trend but not significantly different(P>0.05,P>0.05);expression of CRH mRNA in hypothalamus was on a downward trend but not significantly different(P>0.05);expression of GR mRNA in hippocampal was on a upward trend but not significantly different(P>0.05);expression of GR mRNA in the lung tissues was significantly reduced(P<0.05).(4)Compared with the challenge model group:the open-arm entries and the percentage of open-arm entries of sensitization chiropractic group were not significantly different(P>0.05,P>0.05);the escape latency of orientation navigation experiment was significantly shortened(P<0.05);and the number of crossings in platform quadrant of space exploration experiment were significantly increased(P<0.05);the Penh were markedly reduced when challenged by two high concentration of Ach(P<0.01,P<0.001);the lung HPS,IL-4 and TNF-α level in BALF were significantly reduced(P<0.01,P<0.05,P<0.05);IFN-y level in BALF was on a upward trend but not significantly different(P>0.05);plasma ACTH and CORT level were significantly increased(P<0.05,P<0.05),but not significantly different compared with the normal control group(P>0.05,P>0.05);expression of CRH mRNA in hypothalamus was significantly increased(P<0.001);and expression of GR mRNA in hippocampal was on a downward trend but not significantly different(P>0.05);expression of GR mRNA in the lung tissues was on a upward trend but not significantly different(P>0.05),and not significantly different either Compared with the normal control group(P>0.05).(5)Compared with the challenge model group:the open-arm entries and the percentage of open-arm entries of challenge MP group were not significantly different(P>0.05,P>0.05);in platform quadrant of space exploration experiment in water maze test,the escape latency of orientation navigation experiment and the number of crossings were not significantly different(P>0.05,P>0.05);the Penh were markedly reduced when challenged by two high concentration of Ach(P<0.05,P<0.01);the lung HPS,IL-4 and TNF-α level in BALF were significantly reduced(P<0.01,P<0.05,P<0.01);IFN-γ level in BALF was not significantly different(P>0.05);plasma ACTH level was not significantly different(P>0.05);plasma ACTH and CORT level were on a upward trend but not significantly different(P>0.05,P>0.05);expression of CRH mRNA in hypothalamus was significantly increased(P<0.05);and expression of GR mRNA in hippocampal and lung tissues were not significantly different(P>0.05,P>0.05).ConclusionsAsthma modeling not only caused airway allergic inflammation in the immature rats,but also caused the anxiety and the decrease of ability of learning and memory during the sensitization period and after challenge.Chiropractic therapy intervention could attenuate airway allergic inflammation in asthmatic immature rats,and also effectively improve anxiety and the decline of learning and memory ability,which were partially attributed to its regulation of HPA axis function. |
PDF Full Text Request