BACKGROUND AND OBJECTIVE: Although 5-fluorouracil (5-FU) is a widely used as chemotherapy agent, severe mucositis develops in approximately 80% of patients. 5-FU-induced small intestinal mucositis can cause nausea and vomiting. The current study was designed to investigate peripheral alterations due to the 5-FU-induced mucositis of neuronal and non-neuronal 5-HT3 and NK1 receptor expression by immunohistochemical analysis. METHODS: 5-FU was administered by i.p. injection to C57BL/6 mice. After 4 days, segments of the jejunum were removed. The specimens were analyzed by immunohistochemistry, real-time PCR, and enzyme immunoassay. RESULTS: The numbers of 5-HT3 receptor immunopositive cells and nerve fibers in mucosa were increased by 5-FU treatment. The 5-HT3 receptor immunopositive cell bodies were found only in jejunal submucosa and myenteric plexus in the 5-FU-treated mice. The numbers of NK1 receptor cells in mucosa and immunopositive expression of NK1 receptors in deep muscular plexus were dramatically increased in 5-FU-treated mice. Real-time PCR demonstrated that 5-FU treatment significantly increased mRNA levels of 5-HT3A, 5-HT3B, and NK1 receptors. The amounts of 5-HT and substance P increased after 5-FU treatment. The 5-HT3 or NK1 receptor immunopositive cells colocalized with both 5-HT and substance P. Furthermore, 5-HT3 and NK1 receptors colocalized with CD11b. CONCLUSIONS: The 5-HT3 and NK1 immunopositive macrophages and mucosal mast cells in lamina propria release 5-HT and substance P, which in turn activate their corresponding receptors on mucosal cells in autocrine and paracrine manners. It is assumed to result in the release of 5-HT and substance P in mucosa.
BACKGROUND AND OBJECTIVE: Although 5-fluorouracil (5-FU) is a widely used as chemotherapy agent, severe mucositis develops in approximately 80% of patients. 5-FU-induced small intestinal mucositis can cause nausea and vomiting. The current study was designed to investigate peripheral alterations due to the 5-FU-induced mucositis of neuronal and non-neuronal 5-HT3 and NK1 receptor expression by immunohistochemical analysis. METHODS:5-FU was administered by i.p. injection to C57BL/6 mice. After 4 days, segments of the jejunum were removed. The specimens were analyzed by immunohistochemistry, real-time PCR, and enzyme immunoassay. RESULTS: The numbers of 5-HT3 receptor immunopositive cells and nerve fibers in mucosa were increased by 5-FU treatment. The 5-HT3 receptor immunopositive cell bodies were found only in jejunal submucosa and myenteric plexus in the 5-FU-treated mice. The numbers of NK1 receptor cells in mucosa and immunopositive expression of NK1 receptors in deep muscular plexus were dramatically increased in 5-FU-treated mice. Real-time PCR demonstrated that 5-FU treatment significantly increased mRNA levels of 5-HT3A, 5-HT3B, and NK1 receptors. The amounts of 5-HT and substance P increased after 5-FU treatment. The 5-HT3 or NK1 receptor immunopositive cells colocalized with both 5-HT and substance P. Furthermore, 5-HT3 and NK1 receptors colocalized with CD11b. CONCLUSIONS: The 5-HT3 and NK1 immunopositive macrophages and mucosal mast cells in lamina propria release 5-HT and substance P, which in turn activate their corresponding receptors on mucosal cells in autocrine and paracrine manners. It is assumed to result in the release of 5-HT and substance P in mucosa.
Authors: Deiziane V S Costa; Ana C Bon-Frauches; Angeline M H P Silva; Roberto C P Lima-Júnior; Conceição S Martins; Renata F C Leitão; Gutierrez B Freitas; Patricia Castelucci; David T Bolick; Richard L Guerrant; Cirle A Warren; Vivaldo Moura-Neto; Gerly A C Brito Journal: Sci Rep Date: 2019-01-24 Impact factor: 4.379