[Effect of Different Doses of Herbal Cake-partitioned Moxibustion on Histopathological Changes of Colon Tissue in Ulcerative Colitis Rats]

Abstract

Objective: To observe the effect of different-doses of herbal cake-partitioned moxibustion (Moxi) on histopathological changes of the damaged colon tissue in rats with ulcerative colitis (UC), so as to select an optimal dosage of Moxi in the treatment of UC.

Methods: Sixty-three male Sprague Dawley (SD) rats were randomized into 7 groups: normal control, model, medication, and 1, 2, 3 and 4 moxa-cone Moxi (n＝9 rats per group). The UC model was developed by subcutaneous injection of emulsion (1 mL) containing colon mucosa-prepared protein suspension and complete Freund's adjuvant into the toes, groin and back. On the 38^th day, enema of 3% formalin and the aforementioned emulsion was used. Herbal-cake (composed of monkshood, cinnamon, etc.) partitioned Moxi with 1 or 2 moxa-cones (about 5 min/cone) was applied to bilateral "Tianshu" (ST 25) once daily or once every other day. The rat's general conditions (diet, movement, response ability, stool, and body weight) were observed, and histopathological changes (adhesion, ulcer formation and inflammation) of colon tissues were examined after hematoxylin-eosin (HE) staining, and scored (histopathological score). Gross score was given according to the severity of adhesion, ulcer formation and inflammation of colonic tissues under stereo microscope. The average optical density (AOD) values of colonic mucins were detected after periodic acid-schiff (PAS) staining, and those of the sulfated mucus content detected after high iron dia-mine-alcian blue (HID-AB) staining.

Results: Compared with the normal group, rats in the model group presented loose stool, or with pus and blood, and slowly increased body weight (P<0.01), obvious congestion of colon with ulcer spots or continuous superficial ulcer regions which had irregular glandular cavities, swelling and serious inflammatory infiltration in lamina propria and submucosa, and increased score of colon tissue damage (P<0.01). PAS and HID-AB staining showed a marked decrease of AOD values of colonic mucins and sulfated mucus in the model group relevant to the normal control group (P<0.01), suggesting a reduction of mucus secretion of intestinal glands. Following the intervention, rats in the Moxi groups presented an increase of the body weight, formed feces, and an improvement of the damaged colon tissues as mucosal healing and inflammatory reduction, and a marked decrease of the damage score relevant to the model rats. No significant differences were found in the gross scores among the medication, 1, 2, 3 and 4 moxa-cone groups (P>0.05). The histopathological scores were significantly lower in the 1 and 4 moxa-cone Moxi groups than in the medication group (P<0.05, P<0.01); and significantly lower in the 1, 3, 4 moxa-cone Moxi groups than in the 2 moxa-cone Moxi group (P<0.05, P<0.01). PAS staining showed a significant increase of the AOD values of colonic mucins in the 1, 2, 3 and 4 moxa-cone and medication groups relevant to the model group (P<0.01); and the AOD values of colonic mucins in the 1, 3, 4 moxa-cone Moxi groups were significantly increased than that in the 2 moxa-cone Moxi group (P<0.05, P<0.01). HID-AB staining showed that the AOD values of sulfated mucus content were significantly higher in the 2 and 4 moxa-cone Moxi groups than in the 3 moxa-cone Moxi group (P<0.01). The two-level two-factor factorial analysis showed an interaction existed between the moxa-cone number and Moxi frequency in reducing the gross score and histopathological score and in facilitating colonic mucin and sulfated mucus secretion. The histopathological score of the 4 moxa-cone Moxi group was significantly lower than that of the 2 moxa-cone Moxi group (P<0.05), and the sulfated mucus content was significantly higher in the 4 moxa-cone group than in the 3 moxa-cone group (P<0.01). The effect of Moxi given on alternate days was superior to that of daily Moxi in improving colonic histological damage.

Conclusion: Herbal cake-partitioned moxibustion at ST 25 can promote repair of the damaged colonic tissue and secretion of mucin in UC rats. The number of moxa cones and intervention frequency affect the efficacy of Moxi in improving histopathological changes. The Moxi intervention on alternate days and with 2 moxa-cones every time is recommended.

Keywords: Colonic mucins; HE staining; Herb-partitioned moxibustion; Moxibustion dosage; Sulfated mucus; Ulcerative colitis.