Histopathological Changes in the Periphery of the Sciatic Nerve of Rats after Knee Joint Immobilization

Abstract

[Purpose] This study was performed to investigate the histological changes that occur in the periphery of the sciatic nerve in rats undergoing knee immobilization. [Subjects and Methods] 29 male 9-week-old Wistar rats were divided randomly into a control group (C group, n = 7) and an immobilized group (I group, n = 22). The animals in the I group had the left knee joint immobilized in maximal flexion with plaster casts for two weeks. After the experimental period, we obtained cross-sections of tissues from the center of the left thigh, and the periphery of the sciatic nerve was observed under an optical microscope after hematoxylin-eosin staining. [Results] In contrast to the rats of C group, the rats in I group showed adherence between the bundle of nerve fibers and perineurium, as well as thickening of the perineurium. These histological changes were statistically significant. [Conclusions] Immobilization of the knee joints of rats resulted in characteristic histological changes in the connective tissue around the sciatic nerve.

An immunohistochemical study of the sciatic nerve in a rat knee immobilization model

“…Decreased mobility and plasticity of the nervous system are also considered to cause ROM limitations; however, it remains unclear what changes occur in the nerves and periphery in the setting of contracture due to secondary disabilities or prolonged bed rest. We previously reported strong contact between nerve fiber bundles and the perineurium and decreased perineural spaces in immobilized rats 2 ) . Such contact could decrease nerve fiber bundle mobility and plasticity.…”

Range of Motion Exercise Suppresses Myofibroblast Proliferation in the Joint Capsule in a Rat Joint Contracture Model

“…The joints of the rats in the immobilized group were immobilized, and the animals were housed without any other intervention, whereas the control group was housed without any intervention. The experimental period lasted 2 weeks as in previous studies of our group [30][31][32]. At the end of the experimental period, all rats were euthanized by overdose following intraperitoneal injection of pentobarbital sodium.…”