Methods93maleSPFC57BL/6miceaged6-8wwereselectedandbredunderthefollowinglightconditionsLDgroupmicereceivedlightfrom7:00to19:00(lightintensity110-210IW/cm2),LLgroupreceived24hlight(lightintensity110-210IW/cm2),DDgroupreceived24hdarkallmicewerebredunderLDenvironmentfor7daysthemiceweredividedintothreegroups,LDgroup,LLgroupandDDgroupthemicewerefedfor12-15daysunderthecorrespondinglightcondition。