[Effects of heat-sensitive moxibustion on HPA axis in rats with irritable bowel syndrome]

To observe the effects of heat-sensitive moxibustion on corticotropin releasing hormone (CRH), adrenocorticotrophic hormone (ACTH) and corticosterone (CORT) in rats with irritable bowel syndrome (IBS), and to explore the possible mechanism of heat-sensitive moxibustion on IBS.

According to random number table, 56 SD male rats were randomly divided into a blank group (n=8), a model group (n=8), a moxibustion group (n=32), and a mifepristone group (RU-486 group, n=8). The rats in the blank group were treated with normal feeding; the rats in the model group, RU-486 group and moxibustion group were treated with chronic non-predictable stimulation for 21 days to establish IBS model. After model establishment, the rats in the moxibustion group were treated with moxibustion at "Mingmen" (GV 4) for 40 min, once a day for 14 days; the tail temperature was recorded every 5 min; according to the change of tail temperature, the rats were divided into a heat-sensitive moxibustion group and a non-heat-sensitive moxibustion group, and 8 rats were randomly selected in the two groups. The rats in the RU-486 group were treated with gastric administration of RU-486 for 14 days, while the rats in the blank group, model group and moxibustion groups were treated with identical volume of 0.9% NaCl. The rat general condition, body mass, behavioristics, intestinal propulsive rate and visceral sensitivity were observed in each group; ELISA method was used to detect serum CRH, ACTH and CORT; optical microscope was applied to observe the morphological changes of colon.

(1) After model establishment, rats were in rest state, fatigued, with withered hair and dim ear; the stool was dry or watery; the body mass were slowly increased; the number of crossed grid and standing frequency were significantly reduced; visceral sensitivity was increased and intestinal propulsion rate was decreased; no obvious inflammatory cell infiltration was observed under microscope. (2) After intervention, compared with the blank group, the body mass and visceral sensitivity in the RU-486 group were not significantly different (both P>0.05), but the intestinal propulsion rate was decreased significantly (P<0.01). Compared with the blank group, the body mass of heat-sensitive moxibustion group and non-heat-sensitive moxibustion group was lower (both P<0.01), but the visceral sensitivity and intestinal propulsion rate were similar (both P>0.05). Compared with the model group, the body mass and visceral sensitivity were improved in the RU-486 group (P<0.05, P<0.01), but the intestinal propulsion rate was similar (P>0.05). The body mass, visceral sensitivity and intestinal propulsion rate of the heat-sensitive moxibustion group and the non-heat-sensitive moxibustion group were superior to those of the model group (P<0.05, P<0.01), and the body mass and intestinal propulsion rate of heat-sensitive moxibustion group were superior to those of non-heat-sensitive moxibustion group (both P<0.05). (3) After intervention, compared with the blank group, the contents of CRH, ACTH and CORT in the model group were significantly increased (P<0.05, P<0.01). Compared with the model group, the contents of CRH, ACTH and CORT of the heat-sensitive moxibustion group were statistically reduced (P<0.05, P<0.01), and the contents of CRH and ACTH in the non-heat-sensitive moxibustion group were statistically reduced (P<0.05, P<0.01); the content of CRH in the RU-486 group was reduced (P<0.05), but the contents of ACTH and CORT were increased (P<0.05, P<0.01). Compared with the non-heat-sensitive moxibustion group, the heat-sensitive moxibustion group was better in the improvement of CRH (P<0.05), but there was no significant difference of ACTH and CORT between the two groups (both P>0.05).

Heat-sensitive moxibustion could reduce the contents of CRH, ACTH and CORT through the HPA axis, and improve the function of gastrointestinal motility to treat IBS.