Effect of acrylamide on the degeneration and regeneration of rat myelinated fiber after sciatic nerve crush injury

Qiuyue HE; Manfu HAN; Mingli RAO

ABSTRACT

BACKGROUND:

Ola rats is a kind of rats with genovariation, who displays Wallerian degeneration after peripheral neuroaxonal damage that is slower than that normal 6J rats, thereby additional damage factor may help fully understand the property of Ola rats.

OBJECTIVE:

To observe the effect of acrylamide on the degeneration and regeneration of sciatic nerve medullated fibers following crush injury of C57BL/Ola (Ola) rat and C57BL/6J (6J) rat.

DESIGN:

Randomized controlled experiment.

SETTING:

Department of Neurology,Second People's hospital of Shenzhen; Department of Neurology of First hospital of Jilin University MATERIALS This experiment was carried out in the neurological department in the University of Occupational and Environmental, Japan from January to June 1996. Twelve adult Ola rats and 6J rats were adopted and evenly randomly divided into experimental group and comparison group.

METHODS:

Rats were subjected to general anaesthesia, and then the proximal section of sciatic nerve was exposed and frustrated with hemostatic forceps for 10 s before suture. Rats in the experimental group were given intraperitoneal injection of acrylamide in a total dosage of 350 mg, which replaced by the same volume of physiological saline in comparison group.At 14 days after sciatic nerve torsion injury, all rats were anaesthetized again and the distal section of sciatic nerve was obtained and cut into slices, meanwhile the cross sectional area, the density and size frequency distribution of medullated fibers, as well as the number of medullated fibers in each nerve were determined.MAIN OUTCOME

MEASURES:

The density and size frequency distribution of sciatic nerve medullated fibers, as well as the number, the maximum diameter and the mean diameter of medullated fibers in two group of 0la rats and 6J rats.

RESULTS:

Totally 12 Ola rats and 6J rats entered the result analysis.① No Ola rat displayed Wallerian degeneration; But medullated fiber degeneration and following neonatal small diameter medullated fibers could be observed in 6J rats. ②In the experimental group, the total density of sciatic nerve medullated fibers in 6J rats was lower than that of Ola rat (P ＜ 0.05) ;with the total number of medullated fibers in 6J rats also less than that of Ola rat (P ＜ 0.01 ), which predominated by obviously reduced big diameter fibers (P ＜ 0.01); The mean diameter of medullated fiber in 6J rats was also obviously smaller than that of 0la rat (P ＜ 0.01 ).

CONCLUSION:

The Wallerian degeneration is extremely slow in Ola rat after torsion injury, which cannot be affected by acrylamide; while acrylamide has obvious inhibition on the axonal neogenesis in 6J rat after torsion injury.