[Time-effect study of propylthiouracil-induced thyroid gland hyperplasia].
OBJECTIVE
Establish an effective method for in vivo short-time standardized discriminating system of thyroid hormone disruptors.


METHODS
4 experimental groups treated with PTU lavage for 3, 6, 9, 12 days respectively and one dissolvent group for control. 10 rats in each group were sacrificed in due time with the serum being extracted and detected for T3, T4 and TSH by chemoluminescence. Histopathological changes were visualized by HE staining and changes in colloid were visualized by PAS staining. PCNA was detected by IHC and western-blotting.


RESULTS
Comparing with control group, 3-day treated started to show a decrease in serum concentration of TT3 (P < 0.05), 6-day, 9-day and 12-day treated presented significant decreases in both concentration of TT3 and TT4, with a significant increase in TSH concentration (P < 0.05). Viscera coefficients of thyroid gland were significantly greater than the controls in 6-day, 9-day and 12-day treated groups (P < 0.05). Histopathological observation found thyroid follicle epithelium stratification in 3-day sections, diffused hyperplasia, vast hyperplasia plaque and solid bubbles in 6-day sections (P < 0.05), aggragated fibrilblasts and capillary endothelium hyperplasia and formation of large amount of solid sequential follicles in 9-day sections, mass hollow sequential follicles in 12-day sections. PAS staining showed weak positive in 3-day, 6-day, 9-day thyroid gland follicle colloid sections, and negative in 12-day sections. A coherent of changes with time was observed in PCNA labeling index and PCNA/beta-actin ratio, i.e. starting to increase in 3-day group (P < 0.05), reaching its peak at 6-day group (P < 0.05) and decreasing from 9-day group (P < 0.05), while no significant difference comparing with control in 12-day group.


CONCLUSIONS
Hyperplastic patch, solid bubble and PCNA labeling index detected by IHC used as early index for thyroid gland hyperplasia are stable and relient, and 6 day is optimization experiment phase.
Wang
Yu
Y
Department of Pathology, School of Public Health, Sichuan University, Chengdu 610041, China.
Zhang
Sucai
S
Cheng
Weibo
W
Zeng
Tingting
T
D000818:Animals; D013956:Antithyroid Agents / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006965:Hyperplasia / Q000139:chemically induced; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011441:Propylthiouracil / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013961:Thyroid Gland / Q000187:drug effects* / Q000473:pathology*; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood
D013956:Antithyroid Agents; D018809:Proliferating Cell Nuclear Antigen; D013963:Thyroid Hormones; D014284:Triiodothyronine; D011441:Propylthiouracil; D013972:Thyrotropin; D013974:Thyroxine