## 4 Discussion  
In recent years, the prevalence of aging-related disorders has become a significant challenge due to the increasing population of elderly individuals. Westernized dietary habits have contributed a large part to the rapid increasing numbers of intestinal diseases such as colon cancer, leaky gut syndrome, and IBD [30]. Accordingly, the food industry has begun to discover food materials that can maintain health and treat or prevent various diseases, with increasing interest in gut health, especially in aging-related health. Glasswort contains a variety of physiologically active compounds, including minerals, flavonoids, and phytochemicals [8]. Fermentation of plants offers numerous advantages, including enhanced physiological functional components and improved physical properties [20]. In this study, we examined the impact of fermented glasswort on an animal model of D-gal-induced aging, aiming to elucidate its effects and potential therapeutic applications. D-gal has been commonly used to induce aging in animal models. Excessive intake of D-gal can lead to the production of galactitol through aldose reductase in the body. Galacittol is a toxic metabolite that can increase reactive oxygen species (ROS) production, reduce activation of antioxidant enzymes, and form various oxidized substances. These factors contribute to organ damage and accelerate the aging process [31]. Our study demonstrated that D-gal-induced histological damage of colon was improved in fermented glasswort diet groups such as LGW and HGW groups. H&E staining results revealed  
Figure 6: Relative protein expression levels of TNF-\(\alpha\) (**A**), IL-1\(\beta\) (**B**), and NF-kB (**C**) in colons of D-galactose-induced aging rats. CON, control; CD, control plus D-gal; FOS, fructooligosaccharide plus D-gal; LGW, low glasswort plus D-gal; HGW, high glasswort plus D-gal. Values are presented as the means \(\pm\) SEM for eight rats in each group. Statistically significant difference (* \(p\) < 0.05) was determined by one-way ANOVA followed by Tukey’s test for multiple comparisons. n.s., not significant. considerable crypt damage in the CD group, whereas fermented glasswort groups exhibited less pronounced crypt damage. Previous studies have reported that aged mice show significantly increased inflammatory cell infiltrate, depletion of goblet cells, and crypt abscesses in colon compared to adult mice [32]. Stem cells in the gut are present at the base of the colonic crypt. They produce various cells. However, with aging, the function of these stem cells declines in tissues such as the skin, brain, bone, and gut. Age-related disorders are caused by stem cells exhaustion [33]. Four different types of intestinal epithelial cells, columnar cells, goblet cells, neuroendocrine cells, and Paneth cells, are produced by intestinal stem cells [34]. Goblet cells can secrete glycoprotein mucin, a major component of the intestinal mucus. Mucus plays an important role in protecting the gastrointestinal tract. It has been reported that the two mucus layers of the colon are constituted by MUC2 mucin [35]. Continuous damage to the intestine can result in destruction of crypts known to protect intestinal stem cells, leading to a decrease in goblet cell number. Results of staining colon tissues shown in Figure 2 revealed that goblet cells damage was effectively prevented in fermented glasswort groups such as LGW and HGW groups where the CD group exhibited depletion of goblet cells. In addition, trends of goblet cell numbers showed a similar pattern to changes observed for mucus layer thickness (Figure 3). Recent studies have shown that aging is associated with increased apoptosis of goblet cells, reduced abundance of beneficial bacteria such as _Akkermansia_ spp., and decreased expression of genes related to immune function [36].