The β-defensins are integral member of the innate immune system, being the first line of defense against microbial pathogens at the epithelial surfaces of many organs, including the digestive tract. It is known that mouse β-defensin 3 (mBD-3) is downregulated in the epidermis under stress conditions. To ascertain whether stress modulates β-defensins, we assessed mBD-3 mRNA expression levels in the upper digestive mucosa in mice.
Method:
In an animal model of type 2 diabetes, we used 20 male NSY/Hos mice at age 26 weeks. Ten mice received a high-fat diet (HF group); the other mice received a normal diet (ND group). As the stress group, each 5 mice of the HF group and ND group were placed in restricted conditions for 16 hours at night for 3 days. The remaining mice constituted the non-stress group. The mBD-3 mRNA expression levels in the gingiva, esophagus, and stomach were measured by real-time PCR. Statistical analysis were performed using the Kruskal-Wallis test and the Mann-Whitney U test. A P value less than 0.05 was considered significant.
Result:
The mBD-3 mRNA expression levels among the gingiva, esophagus and stomach showed significant differences (P<0.05). In particular, high mBD-3 mRNA expression was detected in the gingiva compared with the esophagus and stomach (P<0.05). In the esophagus, the mBD-3 mRNA expression levels in the stressed mice were significantly lower than in the non-stressed mice of the HF group (P<0.05), but the mBD-3 mRNA expression levels of the gingiva or stomach were unchanged.
Conclusion:
The mBD-3 in the gingiva may be an important factor in defending in the upper digestive mucosa. Since stress downregulated mBD-3 mRNA expression in the esophageal mucosa, stress may be a factor in modulating mBD-3 expression levels.