Figure 1.
T2 maps demonstrating the evolution of TBI lesion volumes (two upper rows) from representative low dose methamphetamine treated (T) and saline treated (C) TBI rats.
The two lower rows are also T2 maps, which demonstrate the evolution of ventricular expansion for treated (T) and control (C) rats. Although the T2 maps obtained at 6 weeks after TBI showed smaller lesion and ventricular volumes in the treated rats (the 1st and 3rd rows) compared with the control rats (the 2nd and 4th rows), no statistically significant differences were found between the treated (n = 10) and control (n = 10) groups during the 6 weeks after TBI.
Figure 2.
Lesion (A) and ipsilateral ventricular (B) volumes measured on T2 maps after TBI were charted for both treated (n = 10) and control (n = 10) rats.
Although the lesion and ventricular volumes were smaller in the treated rats, i.e. evident at 4 weeks for lesion and 3 weeks for ventricle after TBI, than that in the control rats, no statistically significant differences were found between the two groups during the 6 weeks after TBI. Normalized FA values (C) of recovery area demonstrated significant differences between the groups starting 3 weeks after TBI in rats. T2 values of both core and recovery regions (D) did not show statistical differences between the two groups in 6 weeks after TBI; however, significant differences were observed between core and recovery regions starting 2 weeks after TBI for all rats.
Figure 3.
Measurements of densities of MAP-2 staining (A), SMI-32 staining (B), and BLFB staining (C), demonstrated that low dose methamphetamine treatment of TBI significantly increases neurons density and axonal reorganization in the ipsilateral hemisphere in rats.
However, no differences were found for synaptophysin staining (D). No differences were found with immunohistochemical density stainings in the contralateral hemisphere of rat brain after TBI.
Figure 4.
Functional tests demonstrated that low dose methamphetamine treatment significantly lowered mNSS (A) and reduced foot faults (C: forelimb; D: hindlimb) in treated rats starting at 1 week after TBI.
However, no differences were observed in Morris water maze test (B) between the treated and control rats.
Figure 5.
An ex vivo MRI scan of a control rat q-ball map (A), which is enlarged (B) to view fiber crossing, showed few crossing fibers (blue and yellow arrow heads) surrounding the TBI lesion core (E, cyan arrow).
Both SD (C) and FA (D) maps detected the reorganized white matter (blue and yellow arrow heads), which was consistent with BLFB staining (blue and yellow arrow heads in H; G: 4× enlarged, red frame in F; H: 10× enlarged, yellow frame in G).