Objective To observe the histological and ultrastructural changes of the otopoint “Stomach”(MA-IC) area in chronic gastritis rabbits so as to provide a foundation for auricular acupoint diagnosis and treatment. Methods A total of 20 New Zealand rabbits(half male and half female) were randomly and equally divided into control and model groups. The chronic gastritis model was established by gavage of 5% sodium salicylate each day for 5 weeks

while the rabbits of the control group received gavage of clear water at the same volume. Morphological changes of the tissues of gastric mucosa

otopoint “Stomach” and auricular control point were observed under light microscope after staining with hematoxylin-eosin(H.E.)

and given scores(0-3 points) according to the levels of inflammatory cells. The ultrastructural changes of the otopoint “Stomach” tissue were observed under transmission electronic microscope(TEM). Results H.E. staining revealed smoothness of the gastric smooth muscle with no or a few of inflammatory cells in the control group

and appearance of gastric mucosal hemorrhage and erosion

slightly disordered epithelial glands and infiltration of a large number of lymphocytes in the mucosal layer with some clustered lymphocyte aggregation foci in the model group. The pathological score of gastric mucous in the model group was significantly higher than that in the control group(P<0.01). Under light microscope

no obvious changes were observed in the skin of the otopoint “Stomach” of the control group and the control point of the model group

whereas hyperplasia and abscission in the epidermic cuticle and spinous layer and basal layer

dermal tissue and inflammatory cell infiltration were observed in the otopoint “Stomach” of the model group. Results of TEM observation showed no significant changes in the ultrastructure of the otopoint “Stomach” in the control group

and swollen and vacuolated epidermal keratinocyte mitochondria

reduced keratin filament aggregation

widened local cell space

unclear desmosome structure

activation of the dermal fibroblasts

and an increase of the myelinated nerve mitochondria in the “Stomach” region in the model group. Conclusion The otopoint “Stomach” tissue has structural damage and hyperplasia in chronic gastritis rabbits

suggesting a special correlation between the otopoint “Stomach” and gastric tissue

hence

providing a morphological basis for otopoint diagnosis and treatment.