Effect of Radiation on Sucrose Detection Thresholds of Mice

Abstract

Radiotherapy is one of the most common treatments for head and neck cancers, with an almost obligate side effect of altered taste (Conger AD. 1973. Loss and recovery of taste acuity in patients irradiated to the oral cavity. Radiat Res. 53:338-347.). In mice, targeted irradiation of the head and neck causes transient repression of proliferation of basal epithelial cells responsible for taste cell replacement, leading to a temporary depletion of taste sensory cells within taste buds, including Type II taste cells involved in detection of sweet stimuli (Nguyen HM, Reyland ME, Barlow LA. 2012. Mechanisms of taste bud cell loss after head and neck irradiation. J Neurosci. 32:3474-3484.). These findings suggest that irradiation may elevate sucrose detection thresholds, peaking at 7 days postirradiation when loss of Type II cells is greatest. To test this hypothesis, sucrose detection thresholds (concentration detected in 50% of presentations) were measured in mice for 15 days after treatment of: 1) irradiation while anesthetized, 2) anesthetic alone, or 3) saline. Mice were trained to distinguish water from several concentrations of sucrose. Mice were irradiated with one 8 Gy dose (RADSOURCE-2000 X-ray Irradiator) to the nose and mouth while under 2,2,2-tribromethanol anesthesia (Avertin). Unexpectedly, mice given anesthesia showed a small elevation in sucrose thresholds compared to saline-injected mice, but irradiated mice show significantly elevated sucrose thresholds compared to either control group, an effect that peaked at 6-8 days postirradiation. The timing of loss and recovery of sucrose sensitivity generally coincides with the reported maximal reduction and recovery of Type II taste cells (Nguyen HM, Reyland ME, Barlow LA. 2012. Mechanisms of taste bud cell loss after head and neck irradiation. J Neurosci. 32:3474-3484.). Thus, even a single dose of irradiation can significantly alter detection of carbohydrates, an important consideration for patients undergoing radiotherapy.

Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion

“…SK54510) around the maxillary left second molar with a slight modification of the previously described procedure under anesthesia in order to induce periodontitis [ 51 ]. The animals were anesthetized via an intraperitoneal injection of Avertin (Sigma-Aldrich, USA), as previously described [ 66 ]. After 5 days, the ligature was removed, and the second molar was extracted, which formed the extraction socket [ 34 ].…”

Effects of oleanolic acid acetate on bone formation in an experimental periodontitis model in mice

“…To induce periodontitis, anesthetized mice were ligated with black silk 5‐0 (SK54510, AILEE CO, LTD, Korea) around the maxillary left second molar with a slight modification of the previously described procedure . The animals were anesthetized by an intraperitoneal injection of Avertin (Sigma‐Aldrich, USA) as previously described . Four mice with ligature were sacrificed to harvest maxilla with an intact palate.…”

“…9,22 The animals were anesthetized by an intraperitoneal injection of Avertin (Sigma-Aldrich, USA) as previously described. 23 Four mice with ligature were sacrificed to harvest maxilla with an intact palate. Harvested maxillae were dissected to separate the left experimental and right control half hemi-maxillae, which were autoclaved in phosphate-buffered saline for 15 minutes.…”

Fractionated head and neck irradiation impacts taste progenitors, differentiated taste cells, and Wnt/β-catenin signaling in adult mice

“…While this study was the first to comprehensively explore the impact of IR on taste bud cell renewal 17 , a single dose paradigm does not reflect conventional fractionated IR experienced by patients. In contrast to the rapid recovery of taste bud homeostasis as well as taste function in mice following a single dose 17,18 , patients can suffer from taste disturbance for months and even years following fractionated IR 14,19,20 . Here, we sought to establish how at a cellular level, taste homeostasis is affected by repeated IR.…”