Comparative proteomics of the ewe cerebrospinal fluid under long or short photoperiod

Photoperiod, the main physical synchronizer of seasonal functions, is now acknowledged as a key player for the modulation of molecule access to cerebrospinal fluid (CSF). From previous work showing a different transfer rate from steroids or protein hormones from blood to CSF according to photoperiod and, a modulation of choroid plexus (CP) tight junction protein content with photoperiod, we hypothesized that CSF proteome under long days (LD) would differ from that of CSF sampled under short days (SD) in ovariectomized-estradiol replaced ewes. CSF protein expression variability between SD- or LD-treated ewes was therefore studied from pools of CSF collected for 48H from ewes of similar age and weight.