The effect of temperature on the maturation of regenerating peripheral nerves in the rat
Jha, B.D.; Goldby, F.; Gamble, H.J.
Journal of Anatomy 93: 436-447
ISSN/ISBN: 0021-8782 PMID: 14407268 Accession: 023859296
The rates of maturation of the regenerating sural and genito-femoral nerves of the rat were studied in 3 different environments, hot (34-37[degree]C), warm (20-22[degree]C) and cold (3-8[degree]C). The stage of maturation after varying periods up to 150 days after injury by crushing was estimated from (i) the total number of myelinated fibers present, (ii) histograms showing the fiber caliber distribution, (iii) the total cross-sectional area of the fibers in the whole nerve. Fifty days after injury, significant differences in the stage of maturation reached were demonstrated in the sural nerve, between the hot and warm and between the warm and cold specimens. At all periods studied there were significant differences between the hot and the cold specimens. Smaller differences, many of which were not statistically significant, were found between the hot and warm and between the warm and cold specimens, but the uniform trend of the results suggested that a study of larger groups of specimens would show these smaller differences to be significant. It was found that the rate of maturation in the genito-femoral nerve regenerating in the uniform temperature of the peritoneal cavity was not affected by different environmental temperatures. It was concluded that the effect on the sural nerve must have been due to the influence of the temperature on the peripheral (subcutaneous) part of the sural nerve. The extent of subcutaneous cooling achieved in the environmental temperatures used was of the order of 1-2[degree]C between the hot and the warm animals and about 4[degree]C between the warm and the cold animals.