Zahra Soltani, Mohammad Khaksari, Sedigheh Amiresmaili, Vida Naderi, Elham Jafari and Nader Shahrokhi
Our previous studies have demonstrated that estrogen is protective in traumatic brain injury (TBI). However,
concerns about negative consequences of estrogen therapy have led to find other strategies to obtain estrogen’s
benefits in the brain, including the use of a soy diet. This study was designed to determine whether a soy diet is
protective in TBI. The male Albino N-Mary rats received either a soy- free diet (SFD) or soy diet (SD) from weaning
to adulthood. The SFD and SD rats were separately divided to two groups of sham and TBI (n= 18 in each group).
The diffuse and severe brain injury was induced by Marmarou method. The disruption of Blood brain- barrier (BBB)
was evaluated 48 h post- TBI. The intracranial pressure (ICP), the neurologic outcome, and the beam-walk task
(WB) were determined before trauma, on trauma day (D0), and first (D1) and second (D2) days post- TBI. Evans
blue dye was significantly high in the SFD + TBI group vs. other groups. The ICP was significantly high in the SFD +
TBI group in all times evaluated, and in the SD + TBI group on D1 and D2, however lower than that in the former
group. The neurologic outcome score was significantly low in the SFD + TBI group vs. the sham groups in all times.
Also the traversal time in WB task was significantly high in the SFD + TBI group not the SD + TBI group, vs. the
sham groups in all times, however significant difference of distance traveled was shown only on trauma day. The
results of this study demonstrate that soy diet can prevent the disruption of BBB, and attenuate the elevation of ICP,
and the disturbance of vestibulomotor and neurologic performance in TBI.