[Effect of Dendrobium officinale on Yin deficiency constipation induced by warm-drying medicine in mice]

Dendrobium officinale is a sacred product for nourishing Yin and has a clear "thick gastrointestinal" effect. Modern pharmacological studies had found that it could improve gastrointestinal function. This study observed the improvement effect of D. officinale on constipation model mice with Yin deficiency caused by warm-drying medicine. It provided experimental basis for the treatment of Yin deficiency constipation. The male and female ICR mice were randomly divided into normal group, model group, D. officinale high, medium and low dose groups(0.6, 0.4, 0.2 g·kg~(-1)), and phenolphthalein tablets group. The model mice of Yin deficiency constipation were established by gavage with warm-drying medicine. The overall state and body temperature of the mice were observed and recorded. The number of feces, feces weight, fecal moisture content and intestinal propulsion were measured. The morphological damage of colon tissue was observed by hematoxylin-eosin(HE) staining. The expression of inducible nitric oxide synthase(iNOS) in the colon was detected by Western blot and immunohistochemical method. The expression of iNOS mRNA in the colon was detected by Real-time fluorescence quantitative PCR, and the serum cyclic guanosine phosphate(cGMP) level was detected the enzyme-linked immunosorbent assay(ELISA). The results showed that D. candidum could reduce the body temperature of mice with Yin deficiency constipation, increase the number of feces, wet feces, dry feces and intestinal propulsion ability, reduce the expression of iNOS protein and mRNA in the colon, and reduce the content of cGMP in the serum. It showed that D. candidum could improve the symptoms of Yin deficiency constipation mice caused by warm-drying medicine, and the mechanism may be related to reducing the expression of iNOS in the colon and increasing intestinal motility.