title: Structural and functional characteristics of irradiation damage to parotid glands in the miniature pig.
abstract: OBJECTIVE
  To evaluate the effects of a solitary megadose protocol of ionizing radiation (IR) on the structure and function of the miniature pig (minipig) parotid gland.
  
  
  METHODS
  Fourteen minipigs were subjected to either 15 or 20 Gy to one parotid gland with a linear accelerator, whereas another four minipigs served as non-IR controls. Salivary flow rates and salivary chemistries were measured pre-IR and 4 and 16 weeks post-IR. A quantitative assessment of gland weight and acinar area and detailed serum chemistry and hematologic analyses were also performed.
  
  
  RESULTS
  Parotid flow rates decreased by approximately 50% either with 20 Gy at 4 weeks, or 15 Gy at 16 weeks post-IR. In the 20 Gy group, salivary flow rates were reduced by approximately 80% at 16 weeks post-IR. A significant decrease in salivary calcium and amylase and an increase of salivary potassium levels were found in both IR groups. There were also transient alterations in serum chemistry and hematology parameters post-IR. Parotid gland weights were significantly decreased (-50%) in the 15 and 20 Gy groups at 4 and 16 weeks post-IR. Additionally, the acinar cell area in glands of both IR groups was significantly reduced from that in control glands at both the 4 and 16 weeks time points.
  
  
  CONCLUSIONS
  Structural changes in salivary gland parenchyma occurred relatively early after IR, whereas the alterations in salivary output were relatively delayed. Further, reductions in salivary flow were not proportional to acinar cell area loss. Together, these findings suggest that nonparenchymal IR damage likely contributes to IR-induced salivary hypofunction.
authors: Salivary Gland Disease Center and Molecular Laboratory for Gene Therapy, Faculty of Stomatology, Capital University of Medical Sciences, Beijing, PR China.
authors: Jun
authors: J
authors: Li
authors: Zhaochen
authors: Z
authors: Shan
authors: Guangfei
authors: G
authors: Ou
authors: Xiaoyong
authors: X
authors: Liu
authors: Chunmei
authors: C
authors: Zhang
authors: Bruce J
authors: BJ
authors: Baum
authors: Songlin
authors: S
authors: Wang
mesh_terms: D000681:Amylases / Q000378:metabolism; D000818:Animals; D009929:Organ Size / Q000528:radiation effects; D010306:Parotid Gland / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D011833:Radiation Injuries, Experimental / Q000378:metabolism / Q000473:pathology*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism*; D013552:Swine; D013556:Swine, Miniature
chemical_list: D000681:Amylases