ObjectiveTo compare the protective effects of water extracts from fresh and dried Dendrobium huoshanense on gastric mucosa in chronic atrophic gastritis （CAG）. MethodsMale SD rats （n=72） were randomly divided into 9 groups， with 8 rats in each group， which were normal group， model group， Yangwei Shu （4 g·kg^-1） group， low-， medium-， and high-dose fresh D. huoshanense （3.5， 7， and 14 g·kg^-1） groups， and low-， medium-， and high-dose dried D. huoshanense （0.7， 1.4， 2.8 g·kg^-1） groups. The CAG rat model was successfully established by inducing with N-methyl-N'-nitro-N-nitrosoguanidine （MNNG） and other factors for a total of 11 weeks. Then， the rats were intervened with fresh and dried D. huoshanense for 4 weeks. The serum and gastric tissues of the rats were collected. The changes in gastric juice secretion volume and gastric acid pH value in each group were observed. The gastric mucosal injury was observed by naked eyes and hematoxylin-eosin（HE） staining. The gastric mucus secretion level was determined by Alcian blue and periodic acid-Schiff staining（AB-PAS） staining. The expression levels of tight junction proteins Occludin and ZO-1 in gastric tissues were determined by immunofluorescence. The expression levels of serum pepsinogen Ⅰ （PG Ⅰ）， pepsinogen Ⅱ （PG Ⅱ）， gastrin 17 （G-17）， interleukin-1β （IL-1β）， interleukin-6 （IL-6）， and tumor necrosis factor-α （TNF-α） were determined by enzyme-linked immunosorbent assay （ELISA）. The expression levels of aquaporin 1 （AQP1）， aquaporin 3 （AQP3）， and aquaporin 4 （AQP4） in gastric tissues were determined by Western blot. ResultsCompared with the normal group， the model group showed an obviously reduced gastric juice secretion volume （P0.05）， significantly increased gastric acid pH value （P0.01）， gastric mucosa with obvious atrophy， and a significantly reduced gastric mucus secretion volume （P0.01）. The expression of Occludin and ZO-1 in the gastric mucosal barrier was significantly decreased （P0.01）. The levels of PG Ⅰ and PG Ⅱ in the serum were obviously decreased （P0.05， P0.01）， and the levels of G-17， IL-1β， IL-6， and TNF-α were significantly increased （P0.01）. The expression level of AQP1 in the gastric tissue was significantly upregulated （P0.01）， and the expression levels of AQP3 and AQP4 were significantly downregulated （P0.01）. Compared with the model group， each drug administration group could improve the gastric mucosal atrophy of CAG model rats to varying degrees， obviously increase the gastric juice secretion volume of the model rats （P0.05， P0.01）， significantly decrease the gastric acid pH value （P0.01）， obviously increase the gastric mucus secretion volume （P0.05， P0.01）， obviously decrease the expression levels of G-17， IL-6， IL-1β， and TNF-α （P0.05， P0.01）， obviously increase the expression levels of Occludin， ZO-1， PG Ⅰ， and PG Ⅱ （P0.05， P0.01）， obviously upregulate the expression levels of AQP3 and AQP4 （P0.05， P0.01）， and obviously downregulate the expression level of AQP1 （P0.05， P0.01）. ConclusionThe water extracts of fresh and dried D. huoshanense can exert therapeutic effects on CAG by improving gastric mucosal injury， reducing inflammation， and regulating water metabolism. Moreover， the dried D. huoshanense has a better effect.