Table I.

Summary of quantified histological changes after the DEN treatment.

Group	Weeks	No.	Degenerated hepatocytes	Oval cells	Renewed hepatocytes	Hyperplastic nodules	HCC	Fibrosis
Control
	4	301	0	0	0	0	0	0
		302	0	0	0	0	0	0
	6	303	0	0	0	0	0	0
		304	0	0	0	0	0	0
	8	305	0	0	0	0	0	0
		306	0	0	0	0	0	0
	10	307	0	0	0	0	0	0
		308	0	0	0	0	0	0
	12	309	0	0	0	0	0	0
		310	0	0	0	0	0	0
	14	311	0	0	0	0	0	0
		312	0	0	0	0	0	0
DEN
	4	501	0	0	0	0	0	0
		502	0	0	1	0	0	0
		503	0	0	0	0	0	0
		504	0	0	0	0	0	0
	6	505	1	0	1	0	0	0
		506	1	0	1	0	0	1
		507	1	1	1	0	0	1
		508	0	0	0	0	0	0
	8	509	2	0	1	0	0	1
		510	2	1	1	0	0	1
		511	2	1	1	0	0	1
		512	2	1	1	0	0	1
	10	513	2	1	1	0	0	1
		514	2	1	1	0	0	1
		515	2	1	1	0	0	1
		516	2	1	1	0	0	1
	12	517	1	1	2	1	0	2
		518	1	1	2	2	0	2
		519	1	1	2	1	0	1
		520	1	2	2	1	0	1
	14	521	1	2	2	2	0	1
		522	2	2	2	1	0	2
		523	1	2	2	1	0	2
		524	2	2	3	2	0	2

0, none; 1 <5%; 2, <50%; 3, ≥50%. DEN, diethylnitrosamine; HCC, hepatocellular carcinoma.