Sciatic Nerve Regeneration in Wistar Albino Rats Evaluated by in vivo Conductivity and in vitro 1H NMR Relaxometry

Abstract

Objective: The aim of this study was to evaluate and quantify functional and structural nerve regeneration after reconstruction using either direct suture or silicon graft.Methods: Thirty-two adult Wistar Albino rats were divided in two equal groups. The left sciatic nerve was cross-sectioned and reconstructed using either direct suture (DS group) or a silicone graft (SG group). At 4, 6, 8 and 10 weeks two rats were randomly chosen from each group for in vivo measurement of nerve electric conductivity and subsequently sacrificed together with other two rats from the same group for in vitro 1H NMR relaxometry measurements. The T2 distributions were assigned to 1H located in different pools corresponding to the nerve structure.Results: In the injured nerve we observed a significant increase in the stimulation threshold and a decrease in conduction velocity when compared with the healthy nerve in both groups. Whereas the conduction velocity increased progressively from 4 to 10 weeks in the DS group, the opposite evolution was observed in the SG group. In both groups, the first two peaks corresponding to water bound to collagen and epineurium had smaller transverse relaxation times in the injured nerves, while there was no change in the peaks corresponding to perineurium and free water between healthy and injured nerves.Conclusions: Significant differences were observed between direct suture and nerve graft reconstructions from both a functional and structural point of view. In the case of direct suture reconstruction, the nerve was functionally healed at 10 weeks after injury.

Influence of the Extraction Solution on the Removal of Heavy Metals from Polluted Soils

“…Soil macrotexture was determined by the sieving method for separating particles larger than 2 mm (forming the skeleton) and coarse sand (2–0.2 mm) and by the sedimentation method in a still column of water (Kubiena pipetting method/Kacinski method), based on the theory that the velocity of falling particles in a liquid depends on their size for separating grain size fractions smaller than 0.02 mm [ 88 , 91 ]. Subsequently, the particle size fractions of fine sand (0.2–0.02 mm), coarse dust (0.02–0.01 mm), fine dust (0.01–0.002 mm), and clay with aid (<0.002 mm) were calculated [ 91 , 92 ].…”