Table 2. The incidence of EAT and the mean score for intrathyroidal mononuclear cell infiltration in coumestrol-exposed mice and the vehicle controls.

Group	Incidence	Histological severity of thyroiditis (score/n)						Mean score
		0	1	2	3	4	5
Control group	86.0%	2	5	3	3	1	0	1.72
L group	75.0%	4	8	1	3	0	0	1.19
H group	66.7%	5	1	7	2	0	0	1.40

Female adult CBA/J mice were randomly divided into three groups. They were exposed to the drinking water containing 1% Tween80 only (Control group), 0.8 mg/l coumestrol in 1% Tween80 (L group), 8 mg/l coumestrol in 1% Tween80 (H group), respectively. All these mice were further immunized twice with mouse thyroglobulin and Freund's adjuvant at a two-week interval. The extent of mononuclear cell infiltration was observed under a light microscope after thyroid sections were stained with hematoxylin and eosin.