Quantitative evaluation of direct application of vitamin A on the regeneration of sciatic nerve fiber after crush injury

ABSTRACT

Direct application of low dose of vitamin A [1000 IU] immediately on crush injured sciatic nerve [2mm X 2sec.] of rates once or twice 12 days apart improved significantly the internodal length-L, in micro M[X +/- sem] 8 weeks post-injury, [288 +/- 6.63 and 345.82 +/- 11.21, respectively] relative to the control [182.59 +/- 6.49]. similar trend was observed in the improved diameter - D [8.16 +/- 0.13 and 8.41 +/- 0.81] relative to the control [6.94 +/- 0.19]. Similar dose of vitamin A was injected I.m. [2x/wk/4 wks] for comparison and showed an improved internodal length [252.39 +/- 6.39] and diameter [8.06 ' 0.19], but the animals indicated depressed gain in body weight. All vitamin A treated rats showed 5-6% very short internodes [<150 micro M] while in the control it was very high [29%]. Frequency distribution analysis of the length revealed despite an increase in mode length of 100 micro M over the control, the curves showed for 1st time moderate slope when they descend to the right while in the control the curve descends with sharp slope. Apparently, direct application of vitamin A on crush injuried sciatic nerve improved the regenerated L and D and bears no unwanted side effects. This is an advantage over previous works where high oral dose of vitamin A and/or colchicines i.m produced similar improvements but the treated animals showed signs of toxicity as indicated by depressed weight gain