DTI-MRI at 2 days after spinal cord injury accurately predicts long-term locomotor function recovery in rats.

OBJECTIVE: Spinal cord injury (SCI) damages an individual's sensory, motor, and autonomic functions and represents a social emergency, mostly in developed countries. Accurate and timely diagnosis of the severity of SCI must be carried out as quickly as possible to allow time for drug and therapy testing in the early stages after injury. MATERIALS AND METHODS: Male Dark Agouti (DA) rats underwent spinal cord cryoinjury at the T13 level of the spine. Under typical conditions, in vivo magnetic resonance imaging (MRI) T2 and echo-planar imaging - diffusion tensor imaging (EPI-DTI) examinations were conducted. This involved the reconstruction of nerve tracts and the measurement of the fractional anisotropy (FA) index, as well as measurements of the ratio of Hyper/Hypo intensive areas and spinal cord injury severity scores. RESULTS: Our study shows that, after cryoinjury, the FA significantly decreased in all animals. An increase in FA level, derived from EPI-DTI within 2 days after SCI, accurately predicts long-term locomotor function recovery. In rats with higher FA, recorded on day 2 after injury, complete restoration of locomotor function was observed, while at low FA values, the animals maintained stable monoplegia. CONCLUSIONS: Our results, though validating the T2 10-grade MRI scale for SCI, indicate that FA would represent the MRI technical instrument, which would better monitor the evolution of SCI and, accordingly, better objectively evaluate the impact of potentially therapeutic protocols for spinal cord traumatic injury. Despite the results achieved, significant difficulties must be overcome on the way to successful clinical implementation of the findings in humans.

[Structure and venous vascular bed of the rectum in Stavropol breed sheep].

This investigation was aimed at the study of macromorphology of the rectum, including its intramural and extraorgan venous vascular bed in 18-month-old sheep of Stavropol breed. The methods used included anatomical preparation, morphometry, contrast mass intravascular injection, separation of an intestinal wall into the individual layers and preparation of total samples. The thickness of rectal muscular coat in 18-month-old sheep was found to increase in the caudal direction which is interpreted as an adaptation of the intestine for the evacuation of condensed fecal masses through the anal canal lumen. Intramural rectal venous vascular bed included three plexuses: submucosal, muscular and subserosal. The prevalence of the veins of wide-field type with an index of 90-120 in the rectal wall of a sheep results in the deceleration of the venous blood flow in the organ. At the same time, rectal intramural venous vascular bed possesses higher adaptive capacity in the cases of occlusion of the basic roots due to the well developed collateral network located between the roots of wide-field veins. The major extraorgan venous vessel of sheep rectum is a cranial rectal vein. Presence of its terminoterminal anastomoses with caudal rectal and left colonic veins may provide a bypass rectal venous blood flow in the cases of a the obstruction of one of its major vessels of various etiology.