Effects of acute fluoride exposure in Substance P myenteric varicosities of the small intestine (#129)
Introduction: Substance P (SP) is a neuropeptide
present in enteric neurons, involved not only in the control of intestinal
motility, but also in the development of inflammation in the gastrointestinal
tract (GIT). The increase in the SP production
is associated with the progress of inflammatory process, since SP leads
directly to the secretion of cytokines, such as IL-6,
IL-8, and TNFα. The GIT is considered the main route of F
exposure. Daily, high F concentrations are ingested through dental products,
water and food consumption, and in cases of intoxication, important intestinal
symptoms are described. Aim: To evaluate SP-containing enteric neurons, in the
myenteric plexus of the small intestine, since there is no information about F
effects on enteric neurons, even with the report
of intestinal
symptomatology as result of excessive F intake. Thus, we analysed the
effects of an acute F exposure by the morphology evaluation of the SP
varicosities, which are the axonal portion that concentrates SP. Methods: 12 male rats (Rattus norvegicus - Wistar type) were divided into 2 groups: Control (C) and Acute Dose (AD). The animals
received deionized water for 29 days, and at the 30th day they
received 0 or 25 mgF/kg orally by gavage. The segments of the small intestine
(duodenum, jejunum, and ileum) were collected, and processed for
immunohistochemical technique for the SP identification. Morphometric analyses were carried
out in 400 varicosities from each animal. The groups were compared by Student’s
t-test (p< 5%). Results: The 3 segments (duodenum, jejunum, and ileum) presented a statistically
significant increase (44.6%, 57.1%, and 56.1%, respectively) in the mean value of the
areas of the SP myenteric varicosities for DA in relation to C. Conclusion: we may infer that the dose
of 25mgF/kg could lead to an increase in the production of SP, which could
impair the intestinal motility, and induce an intestinal inflammatory process.