Table 2.

TEC-1 did not induce micronucleus formation in TK9 cells with or without a rat liver microsome fraction (S9).

Group	Test article	Concentration µg/mL	Treatment conditions	Relative population doubling (%)	Micronucleated cells
					Well 1	Well 2	Total	(%)
1	DMSO	10 μL/mL	3 h -S9 mix	100	13	13	26	(0.65)
2	TEC-1	1.9 (4.9 µM)		68.6	13	16	29	(0.73)
3		2.1 (5.4 µM)		65.4	16	20	36	(0.9)
4		2.3 (5.9 µM)		35.0	29	27	56	(1.4) **,##
5	MMC	0.1 (0.3 µM)		N.D.	59	59	118	(2.95) **
6	DMSO	10 μL/mL	3 h + S9 mix	100	10	14	24	(0.6)
7	TEC-1	2.5 (6.4 µM)		76.4	18	15	33	(0.83)
8		2.7 (6.9 µM)		58.7	24	21	45	(1.13) **
9		2.9 (7.4 µM)		46.8	17	13	30	(0.75)
10	CP	6 (21 µM)		N.D.	39	46	85	(2.13) **
11	DMSO	10 μL/mL	24 h -S9 mix	100	18	12	30	(0.75)
12	TEC-1	1.1 (2.8 µM)		81.7	21	13	34	(0.85)
13		1.3 (3.3 µM)		74.4	17	12	29	(0.73)
14		1.5 (3.9 µM)		69.5	17	15	32	(0.8)
15	COL	0.01 (0.03 µM)		N.D.	45	51	96	(2.4) **

Experiments were performed under the following three treatment conditions. 1: short-term treatment for 3 h without S9 mix, followed by a 21-h culture (3 h −S9 mix, shown in groups 1–5), 2: short-term treatment for 3 h with S9 mix, followed by 21-h culture (3 h + S9 mix, shown in groups 6–10), 3: continuous treatment for 24 h without S9 mix (24 h −S9 mix, shown in group 11–15). Mitomycin (MMC) for 3 h −S9 mix, cyclophosphamide (CP) for 3 h + S9 mix, and colcemid (COL) for 24 h −S9 mix were used as positive controls. These articles have been recommended for use in the OECD test guideline (Test No. 487)⁴⁹. DMSO was served as negative control. The numbers of micronucleated cells were counted in 4000 cells and percentages of micronucleated cells were calculated for statistical analyses. ^## < 0.01 as assessed by Cochran-Armitage test for dose-relationship. **p < 0.01 as assessed by Fisher’s exact test using negative control-treated cells. N.D. indicates Not Determined.