Quercetin Supplementation Prevents Changes in the Serotonin and Caspase-3 Immunoreactive Cells of the Jejunum of Diabetic Rats

Abstract

BACKGROUND: Serotonin (5-HT) is present in the epithelial enterochromaffin cells (EC), mast cells of the lamina propria and enteric neurons. The 5-HT is involved in regulating motility, secretion, gut sensation, immune system and inflammation. OBJECTIVE: Evaluate the effects of diabetes and quercetin supplementation on serotoninergic cells and its cell loss by apoptosis in jejunal mucosa of streptozotocin-induced diabetic rats (STZ-rats). METHODS: Twenty-four male Wistar rats were divided into four groups: normoglycemic (C), normoglycemic supplemented with 40 mg/day quercetin (Q), diabetic (D) and diabetic supplemented with 40 mg/day quercetin (DQ). After 120 days, the jejunum was collected and fixated in Zamboni’s solution for 18 h. After obtaining cryosections, immunohistochemistry was performed to label 5-HT and caspase-3. Quantification of 5-HT and caspase-3 immunoreactive (IR) cells in the lamina propria, villi and crypts were performed. RESULTS: The diabetic condition displayed an increase of the number of 5-HT-IR cells in villi and crypts, while decreased number of these cells was observed in lamina propria in the jejunum of STZ-rats. In the diabetic animals, an increased density of apoptotic cells in epithelial villi and crypts of the jejunum was observed, whereas a decreased number of caspase-3-IR cells was observed in lamina propria. Possibly, quercetin supplementation slightly suppressed the apoptosis phenomena in the epithelial villi and crypts of the STZ-rats, however the opposite effect was observed on the 5-HT-IR cells of the lamina propria. Quercetin supplementation on healthy animals promoted few changes of serotoninergic function and apoptotic stimuli. CONCLUSION: These results suggest that quercetin supplementation mostly improved the serotonergic function affected by diabetes maybe due to antioxidant and anti-inflammatory properties of quercetin.

Protective effects of quercetin-loaded microcapsules on the enteric nervous system of diabetic rats

“…This includes protection against various diseases such as osteoporosis, certain forms of cancer, pulmonary and cardiovascular diseases but also against aging (Boots et al, 2008). The use of this antioxidant has proved to be effective in its free form, as demonstrated by previous studies with the enteric nervous system (duodenum, cecum and jejunum), at different doses of daily intake (Lopes et al, 2012;Ferreira et al, 2013;Vieira-Frez et al, 2017;de Souza et al, 2017;Martins-Perles et al, 2019).…”