Table 3. Pairwise comparison for 15 candidate reference genes using comparitive ΔCt method.

Gene		RPS18	ACTB	B2M	GAPDH	PPIA	HPRT1	PGK1	YWHAZ	TBP	UBC	RPS16	RPL13A	RPLP1	SDHA	HMBS	Avg SD	Rank
Rpl13a	Mean	0.49	0.70	4.80	1.66	0.70	6.96	4.60	2.89	7.24	2.17	0.47	–	−0.33	7.49	6.98
	SD	0.30	0.35	0.78	0.30	0.46	0.47	0.59	0.27	0.42	0.38	0.68	–	0.32	0.31	0.29	0.42	1
Ywhaz	Mean	−2.40	−2.18	1.91	−1.23	−2.19	4.07	1.72	–	4.35	−0.72	−2.41	−2.89	−3.22	4.60	4.09
	SD	0.33	0.27	0.76	0.44	0.49	0.46	0.62	–	0.37	0.42	0.74	0.27	0.27	0.28	0.43	0.44	2
Rps18	Mean	–	0.22	4.31	1.17	0.22	6.47	4.12	2.40	6.75	1.68	−0.01	−0.49	−0.81	7.00	6.49
	SD	–	0.41	0.68	0.40	0.48	0.39	0.67	0.33	0.51	0.30	0.66	0.30	0.30	0.38	0.33	0.44	3
Hmbs	Mean	−6.49	−6.27	−2.18	−5.32	−6.27	−0.02	−2.37	−4.09	0.26	−4.81	−6.50	−6.98	−7.30	0.51	–
	SD	0.33	0.54	0.82	0.27	0.38	0.50	0.67	0.43	0.46	0.33	0.55	0.29	0.45	0.35	–	0.45	4
Sdha	Mean	−7.00	−6.79	−2.69	−5.83	−6.79	−0.53	−2.89	−4.60	−0.25	−5.32	−7.02	−7.49	−7.82	–	−0.51
	SD	0.38	0.38	0.83	0.33	0.40	0.49	0.69	0.28	0.43	0.43	0.66	0.31	0.45	–	0.35	0.46	5
Ubc	Mean	−1.68	−1.47	2.63	−0.51	−1.47	4.79	2.44	0.72	5.07	–	−1.70	−2.17	−2.50	5.32	4.81
	SD	0.30	0.53	0.56	0.43	0.51	0.28	0.71	0.42	0.59	–	0.59	0.38	0.40	0.43	0.33	0.46	6
Rplp1	Mean	0.81	1.03	5.13	1.99	1.03	7.29	4.93	3.22	7.57	2.50	0.80	0.33	–	7.82	7.30
	SD	0.30	0.40	0.72	0.49	0.48	0.46	0.64	0.27	0.49	0.40	0.72	0.32	–	0.45	0.45	0.47	7
Gapdh	Mean	−1.17	−0.95	3.14	–	−0.95	5.30	2.95	1.23	5.58	0.51	−1.18	−1.66	−1.99	5.83	5.32
	SD	0.40	0.54	0.92	–	0.37	0.59	0.64	0.44	0.53	0.43	0.60	0.30	0.49	0.33	0.27	0.49	8
Actb	Mean	−0.22	–	4.09	0.95	0.00	6.26	3.90	2.18	6.54	1.47	−0.23	−0.70	−1.03	6.79	6.27
	SD	0.41	–	0.72	0.54	0.63	0.47	0.74	0.27	0.43	0.53	0.82	0.35	0.40	0.38	0.54	0.52	9
Hprt1	Mean	−6.47	−6.26	−2.16	−5.30	−6.26	–	−2.35	−4.07	0.28	−4.79	−6.49	−6.96	−7.29	0.53	0.02
	SD	0.39	0.47	0.44	0.59	0.63	–	0.83	0.46	0.64	0.28	0.75	0.47	0.46	0.49	0.50	0.53	10
Ppia	Mean	−0.22	0.00	4.10	0.95	–	6.26	3.90	2.19	6.54	1.47	−0.23	−0.70	−1.03	6.79	6.27
	SD	0.48	0.63	0.93	0.37	–	0.63	0.74	0.49	0.56	0.51	0.52	0.46	0.48	0.40	0.38	0.54	11
Tbp	Mean	−6.75	−6.54	−2.44	−5.58	−6.54	−0.28	−2.64	−4.35	–	−5.07	−6.77	−7.24	−7.57	0.25	−0.26
	SD	0.51	0.43	0.93	0.53	0.56	0.64	0.65	0.37	–	0.59	0.79	0.42	0.49	0.43	0.46	0.56	12
Rps16	Mean	0.01	0.23	4.32	1.18	0.23	6.49	4.13	2.41	6.77	1.70	–	−0.47	−0.80	7.02	6.50
	SD	0.66	0.82	0.85	0.60	0.52	0.75	0.91	0.74	0.79	0.59	–	0.68	0.72	0.66	0.55	0.70	13
Pgk1	Mean	−4.12	−3.90	0.19	−2.95	−3.90	2.35	–	−1.72	2.64	−2.44	−4.13	−4.60	−4.93	2.89	2.37
	SD	0.67	0.74	1.06	0.64	0.74	0.83	–	0.62	0.65	0.71	0.91	0.59	0.64	0.69	0.67	0.73	14
B2m	Mean	−4.31	−4.09	–	−3.14	−4.10	2.16	−0.19	−1.91	2.44	−2.63	−4.32	−4.80	−5.13	2.69	2.18
	SD	0.68	0.72	–	0.92	0.93	0.44	1.06	0.76	0.93	0.56	0.85	0.78	0.72	0.83	0.82	0.79	15

Note:

Avg SD, average standard deviation (SD) based on ΔCt of gene pairs for each reference gene; Ct, cycle threshold value; Rank, the stability of genes are ranked by Avg SD, and the higher the value, the lower the ranking.