Table 5. Metabolites in lipid extracts from the mouse liver that were significantly different between the normal and UVB groups after 6 weeks and were tentatively identified using nanomate LTQ-MS analysis.

ID	m/z (+)	Adduct	Fold changea	VIPb	p value
LPC 16∶0	496.5	[M+H]+	0.75	2.83	0.004
LPC 18∶1	522.5	[M+H]+	0.63	1.95	0.001
LPC 18∶0	524.5	[M+H]+	0.63	2.68	<0.001
LPC 20∶4	544.4	[M+H]+	0.74	1.17	0.019
LPC 20∶3	546.5	[M+H]+	0.66	0.81	0.014
LPC22∶6	568.5	[M+H]+	0.69	1.16	0.006
PE 34∶2	716.5	[M+H]+	1.16	0.76	0.030
PC 32∶0	734.6	[M+H]+	1.10	1.02	0.028
PE 36∶4	740.5	[M+H]+	1.06	0.82	0.022
PE 36∶2	744.5	[M+H]+	1.11	0.75	0.043
PC 32∶0	756.6	[M+Na]+	1.21	1.44	0.005
PC 34∶2	758.6	[M+H]+	1.23	6.49	<0.001
PE 38∶6	764.5	[M+H]+	1.18	3.14	<0.001
PE 38∶5	766.5	[M+H]+	1.09	1.49	0.006
PC 34∶6	772.6	[M+Na]+	1.13	1.04	0.002
PC 34∶3	778.6	[M+Na]+	1.15	0.75	0.005
PE 39∶6		[M+H]+
PE 38∶5	788.7	[M+Na]+	0.93	1.19	0.030
PE 39∶0	790.5	[M+H]+	1.11	1.40	0.005
PC 35∶1	796.6	[M+Na]+	1.20	2.48	0.018
PE 39∶5	802.6	[M+Na]+	1.15	0.97	0.002
PE 39∶0	812.7	[M+Na]+	0.90	1.95	0.004
PE 40∶6	814.6	[M+Na]+	0.92	0.87	0.008
PC 38∶4	832.8	[M+Na]+	0.92	1.50	0.045
PC 38∶3	834.8	[M+Na]+	0.89	2.32	0.010
PC 38∶2	836.8	[M+Na]+	0.90	1.18	0.004
TG 56∶4	928.6	[M+NH4]+	0.74	0.82	0.048

Variables were selected by VIP value (>0.7) and p value (<0.05) from OPLS-DA models.

^aFold change was calculated by dividing the mean of the peak intensity of each metabolite from the UVB-radiated group by that of the normal group.

^bVIP, variable important in the projection.