Figure 1.
Acute fluid buildup and its detrimental outcome at the contusion lesion site.
A-C. Longitudinal ex vivo view of the lesion site following moderate contusion injury, seen in thionin stained sagittal cord sections at 0, 1, and 4 days PI (postinjury), respectively (n = 3 per time-point). Note the edema, swelling and tissue rupture at 4 days PI. D. Schematic cartoon of fluid accumulation at the lesion site and its sequelae. Bar = 2 mm.
Figure 2.
Midline incision is critical in mitigating the outcome in severe contusion injury.
Plotted are the percent of damaged area in 5 severely contused cord-groups: control, and with midline slits at either 1, 2, 4, or 24 h postinjury (n = 8 per group). Note, myelotomy at 3 time points, 1-4 h, significantly reduced the lesion size and altered the outcome of injury: * p < 0.05; ** p < 0.01. Error bars, SEM.
Figure 3.
Structural repair by radiation therapy made possible by myelotomy.
Micrographs of thionin-stained sagittal sections through normal intact cord and through the epicenter of 3 differently treated severely contused cords seen 90 days postinjury: A. normal; B. control, CNTS; C. incision, CNTS+TOMY; and D. incision followed by radiation therapy, CNTS+TOMY+XRAY. E. Schematic cartoon of the critical role of midline slits in making repair possible (compare with figure 1D); once the secondary damage is halted intrinsic repair can be facilitated by radiation therapy. Note, the tissue preservation and the substantial wound repair in the irradiated cord which contains in its epicenter motoneurons and other neuronal cells. Abbreviations: contusion = CNTS; myelotomy = TOMY; and radiation therapy = XRAY. Bar = 3 mm.
Figure 4.
Midline incision is critical for facilitating repair in severe contusion injury: Ex vivo quantitative data.
Degree of tissue preservation/repair, as measured by area of remaining tissue, in 3 differently treated severely contused cords: control, CNTS (n = 6); incision, CNTS+TOMY (unirradiated, n = 10); and incision followed by radiation therapy, CNTS+TOMY+XRAY (irradiated, n = 7). These 3 groups were either A. without training or B. with treadmill exercised. Note, tissue preservation was enhanced by midline incision from 19% to 26.1%, and radiation therapy increased it to 35% of the normal tissue; further treadmill exercising increased it in the unirradiated from 26.1% to 35% and in the irradiated from 35% to 56.3%. Abbreviations: contusion = CNTS; myelotomy = TOMY; and radiation therapy = XRAY. Significance, * p < 0.05. Error bars, SD.
Figure 5.
Tissue preservation/repair by myelotomy and radiation therapy in vivo.
A. In vivo images of: five serial T2-weighted axial scans of normal, and of 3 differently treated severely contused cords: no added treatment, CNTS; incision, CNTS+TOMY; and incision followed by radiation therapy, CNTS+TOMY+XRAY, at 50 days postinjury (these 3 spinal cord are shown in Fig. 3 B–D). Each of the numbered slices was taken from the same anatomical level of the cord, e.g., slice 1 is at identical level in all 4 cords and mostly unharmed. Note, the ‘fuzziness’ of these images is an innate feature of the acquisition procedure; these are in vivo images that were acquired for about an hour while the animal is breathing, each showing –as a result of the field of view utilized– an enlarged cord (by x7); therefore, to obtain a better view, the figure should be held at a distance. Note, in normal cord some typical anatomical features: the butterfly shaped grey matter (in slice 1), the ventral roots (arrows, slice 2, 4), and the dorsal dark circle (arrowhead in section 1) is a blood vessel. In the injured cords, note sections 3-4 (the lesion epicenter) are abnormal and reduced in size, also the irradiated cord appears to be the least abnormal. Bar = 2 mm. B. Quantitative tissue preservation by myelotomy and radiation therapy. Plotted are the normalized tissue areas in each of the serial MRI sections (2–4) of 4 groups as illustrated in panel A above: normal (n = 3), control (n = 6), unirradiated (n = 8), and irradiated (n = 8). Note, in the control cords tissue decay extends throughout slices 2-4 whereas in those that underwent myelotomy the damage was contained to slices 3-4. Also, tissue preservation in each of the sections is the highest in the irradiated cords in comparison with the control group. Abbreviations: contusion = CNTS; myelotomy = TOMY; and radiation therapy = XRAY. Note, error bars cannot be shown in a 3D plot.
Figure 6.
Hindlimb locomotor function improved by myelotomy and exercising.
The BBB locomotor scores of the 4 differently treated severely contused groups: -⧫- no further treatment (cnts), -•- midline incision (cnts+tomy), -▴- incision and exercise (cnts+tomy+train), and -⊠- incision followed by radiation therapy and exercise (cnts+tomy+xray+train) are plotted as a function of time postinjury. Midline incision and treadmill exercising both increased the hindlimb locomotor performance: going from a severe paralysis of the hindlimb joints to a complete control of the hindlimb movement as defined by Basso et al. [19]; at about 2 months postinjury enhancement became significant and remained thereafter as such for some of the time points tested. Note, comparison for significance was performed between the following: cnts+tomy vs. cnts group; and cnts+tomy+train vs. cnts+tomy group. Significance, * p < 0.05. Abbreviations: contusion = cnts; myelotomy = tomy; and radiation therapy = xray.