Effect of Irradiation on Microvascular Endothelial Cells of Parotid Glands in the Miniature Pig

• Published in: International journal of radiation oncology, biology, physics Vol. 78; no. 3; pp. 897 - 903
• Main Authors: Xu, Junji, D.D.S., Ph.D, Yan, Xing, D.D.S., Ph.D, Gao, Runtao, D.D.S., Ph.D, Mao, Lisha, D.D.S, Cotrim, Ana P., D.D.S., Ph.D, Zheng, Changyu, M.D., Ph.D, Zhang, Chunmei, B.A, Baum, Bruce J., D.M.D., Ph.D, Wang, Songlin, D.D.S., Ph.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2010; Elsevier
• Subjects: ANIMAL TISSUES; ANIMALS; Apoptosis; Aquaporin 1 - analysis; Biological and medical sciences; Biological effects of radiation; Biomarkers - analysis; Biomarkers - metabolism; BLOOD FLOW; BODY; DOMESTIC ANIMALS; Endothelial cells; Endothelial Cells - radiation effects; ENDOTHELIUM; Fundamental and applied biological sciences. Psychology; GLANDS; Hematology, Oncology and Palliative Medicine; In Situ Nick-End Labeling; Ionizing radiations; Male; MAMMALS; MEDICINE; Microvessel density; Microvessels - cytology; Microvessels - radiation effects; MORPHOLOGICAL CHANGES; NUCLEAR MEDICINE; ORGANS; Parotid Gland - blood supply; Parotid Gland - enzymology; Parotid Gland - pathology; Parotid Gland - radiation effects; Platelet Endothelial Cell Adhesion Molecule-1 - analysis; Radiation Dosage; Radiation Injuries, Experimental - enzymology; Radiation Injuries, Experimental - pathology; RADIOLOGY; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Regional Blood Flow - physiology; Regional Blood Flow - radiation effects; SALIVARY GLANDS; Sphingomyelin Phosphodiesterase - analysis; Sphingomyelin Phosphodiesterase - metabolism; Sphingomyelinase; SWINE; Swine, Miniature; THERAPY; Tissues, organs and organisms biophysics; VERTEBRATES; Salivary glands; Radiotherapy; Microvessel density; Sphingomyelinase; Endothelial cells; Biological properties; Endothelial cell; Parotid gland; Digestive system; Toxicity; Salivary gland; Pig; Microcirculation; Vertebrata; Ionizing radiation; Mammalia; Treatment; Animal; Radiation effect; Irradiation; Artiodactyla; Ungulata
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2010.05.048

Purpose To evaluate the effect of irradiation on microvascular endothelial cells in miniature pig parotid glands. Methods and Materials A single 25-Gy dose of irradiation (IR) was delivered to parotid glands of 6 miniature pigs. Three other animals served as non-IR controls. Local blood flow rate in glands was measured pre- and post-IR with an ultrasonic Doppler analyzer. Samples of parotid gland tissue were taken at 4 h, 24 h, 1 week, and 2 weeks after IR for microvascular density (MVD) analysis and sphingomyelinase (SMase) assay. Histopathology and immunohistochemical staining (anti-CD31 and anti-AQP1) were used to assess morphological changes. MVD was determined by calculating the number of CD31- or AQP1-stained cells per field. A terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assay was used to detect apoptotic cells. The activity of acid and neutral Mg2+ -dependent SMase (ASMase and NSMase, respectively) was also assayed. Results Local parotid gland blood flow rate decreased rapidly at 4 h post-IR and remained below control levels throughout the 14-day observation period. Parotid MVD also declined from 4 to 24 hours and remained below control levels thereafter. The activity levels of ASMase and NSMase in parotid glands increased rapidly from 4 to 24 h post-IR and then declined gradually. The frequency of detecting apoptotic nuclei in the glands followed similar kinetics. Conclusions Single-dose IR led to a significant reduction of MVD and local blood flow rate, indicating marked damage to microvascular endothelial cells in miniature pig parotid glands. The significant and rapid increases of ASMase and NSMase activity levels may be important in this IR-induced damage.