HDAC1 and major depressive disorder: In the current study, our behavioral results showed that Vehicle treated TBI mice exhibited significant motor and cognitive impairments, but these dysfunctions were remarkably attenuated by MSCs and MSCs-siHDAC1 transplantation, following by lower mNSS scores and immobility time, better cognitive capacity, and higher sucrose preference index, indicating that MSCs, especially HDAC1-silenced MSCs transplantation can reduce the depression s and improve the neurologic function of TBI mice.