TY - JOUR
T1 - The effect of cervical X-irradiation on activity index of thyrocytes and plasma TSH
T2 - A pre-clinical model for radiation-induced thyroid damage
AU - Van Santen, H. M.
AU - Van Dijk, J. E.
AU - Rodermond, H.
AU - Vansenne, F.
AU - Meertens, N.
AU - Haveman, J.
AU - Endert, E.
AU - De Vijlder, J. J.M.
AU - Vulsma, T.
PY - 2005
Y1 - 2005
N2 - Because radiotherapy in the head and neck region is necessary in the treatment of childhood cancer, possibilities to prevent damage to the thyroid gland must be explored. We developed a model in which radiation-induced effects can be investigated in a way that these effects can be quantified, using thyroid dysmorphology and plasma TSH. Thirty-five Wistar rats, 5 weeks old, were X-irradiated on the cervical region, with a single dose varying from 0 to 20 Gy. After 6 weeks, TSH, T4 and T3 were determined, and thyroid glands were processed for histological examination by two independent pathologists. A histological classification scale was developed, using follicular size, colloid density and cell height of thyrocytes to measure hyperplasia and hypertrophy. By the sum of these scores, a cell-activity index was calculated, which was related to plasma TSH concentration. Numbers of PAS-positive droplets and epithelial desquamation were also counted. Inter-observer reliability was assessed. Good to very good reliability was found for scores of follicular size, colloid density and cell height. Significant increase of cell-activity index was found after 10,15 and 20 Gy. The plasma TSH concentration was positively correlated to the cell-activity index, increasing with radiation-doses up to 15 Gy. The number of desquamated cells was significantly increased after radiation doses >10 Gy, with moderate reliability. In conclusion, this model using cell-activity index of thyrocytes together with plasma thyrotropin concentrations and desquamation of cells can be used for interpretation and future (pre-clinical) studies of prevention of radiation-induced thyroid damage.
AB - Because radiotherapy in the head and neck region is necessary in the treatment of childhood cancer, possibilities to prevent damage to the thyroid gland must be explored. We developed a model in which radiation-induced effects can be investigated in a way that these effects can be quantified, using thyroid dysmorphology and plasma TSH. Thirty-five Wistar rats, 5 weeks old, were X-irradiated on the cervical region, with a single dose varying from 0 to 20 Gy. After 6 weeks, TSH, T4 and T3 were determined, and thyroid glands were processed for histological examination by two independent pathologists. A histological classification scale was developed, using follicular size, colloid density and cell height of thyrocytes to measure hyperplasia and hypertrophy. By the sum of these scores, a cell-activity index was calculated, which was related to plasma TSH concentration. Numbers of PAS-positive droplets and epithelial desquamation were also counted. Inter-observer reliability was assessed. Good to very good reliability was found for scores of follicular size, colloid density and cell height. Significant increase of cell-activity index was found after 10,15 and 20 Gy. The plasma TSH concentration was positively correlated to the cell-activity index, increasing with radiation-doses up to 15 Gy. The number of desquamated cells was significantly increased after radiation doses >10 Gy, with moderate reliability. In conclusion, this model using cell-activity index of thyrocytes together with plasma thyrotropin concentrations and desquamation of cells can be used for interpretation and future (pre-clinical) studies of prevention of radiation-induced thyroid damage.
KW - Hypothyroidism
KW - Morphology
KW - Thyroid gland
KW - Thyrotropin
KW - X-radiation
UR - http://www.scopus.com/inward/record.url?scp=21444460627&partnerID=8YFLogxK
U2 - 10.1007/bf03345383
DO - 10.1007/bf03345383
M3 - Article
C2 - 15952412
AN - SCOPUS:21444460627
SN - 0391-4097
VL - 28
SP - 261
EP - 269
JO - Journal of Endocrinological Investigation
JF - Journal of Endocrinological Investigation
IS - 3
ER -