Altered Chief Cell Morphology in the Gastric Gland of Streptozotocin-Diabetic Rats

Diabetes mellitus (DM) is a metabolic disorder with rising incidences worldwide. Gastric symptoms of DM have been reported, including nausea, vomiting, bloating, and epigastric pain. Moreover, acute to chronic gastritis and atrophic gastritis occur in DM can affect the chief cells of the gastric gland. Chief cells are vital because of their ability to digest and separate vitamin B12 from protein. Lack of vitamin B12 leads to impaired DNA synthesis and abnormal metabolism in red blood cells, and eventually leading to pernicious anemia. Furthermore, decreased vibratory and positional senses, numbness, ataxia with subacute combined degeneration, and dementia are present in pernicious anemic patients. Twenty-four male adult Sprague-Dawley rats were used in this study. The rats were divided into control (n = 12) and diabetic (n = 12) groups. The rats were further separated into two categories: short-term (4 weeks) and long-term (24 weeks) groups. DM model was induced by manually injecting intraperitoneally with streptozotocin in citrate buffer at a dose of 60 mg/kg body weight. The same amount of buffer was injected into the control group. After sacrifice, three regions of the stomach (the cardia, body, and pylorus) were dissected. Histopathology was performed by staining with toluidine blue. Image analysis was used to quantify the zymogen granule accumulation in chief cells. The data were compared between the control and DM rats in each period using Student's t-test. In addition, transmission electron microscopy (TEM) was also used to examine the ultrastructures. There was a significant decrease in the percentage of zymogen granules in DM rats. Under TEM, the destructions of mitochondria, rough endoplasmic reticulum, and Golgi apparatus in the DM rat were observed in the chief cells. In rats with uncontrolled diabetes, there is damage to the chief cells all over the area of the stomach, affecting digestion and malabsorption of vitamin B12. Therefore, this result helps clinicians recognize that diabetic patients with gastric symptoms may have hidden pernicious anemia.