Peripheral Nerve Injury Produces an Increased Expression of Clusterin in Perineuronal Astrocytes

The Peripheral Neuropathy Solution

Neuropathy Solution Program

Get Instant Access

Concomitantly with the response of axotomized motoneurons, astrocytes in their immediate surrounding undergo hypertrophy and express several molecular features of increased activity.1 A structural modification which may be of particular significance for the forthcoming discussion is an increased astrocytic coverage of the axotomized perikarya. This process is probably the consequence of an extensive stripping of presynaptic terminals from the surface of the injured nerve cell bodies, perhaps transiently exposing areas of the neuronal membrane to the extracellular space.

Immunohistochemical preparations demonstrate a distinct increase in clusterin staining intensity in astrocytes in the vicinity of axotomized motoneurons2 and mesencephalic trigeminal nucleus neurons (Pfaller, Liu, Aldskogius, unpublished observations). Similarly, in the spinal cord dorsal horn where primary sensory fibers terminate, astrocytes increase their expression of clusterin and clusterin mRNA following peripheral nerve injury.4 In all these situations the increased immunoreactivity appears to reasonably well match the as-trocytic hypertrophy following peripheral nerve injury. With in situ hybridization for clusterin mRNA, the neuropil labeling is typically relatively weak compared to that of the

Nerve Damage Cartoon

Fig. 8.1. Cartoon summarizing the localization of clusterin upregulation following various types of injury, brain contusion (arrow), lesion (//) of a pathway in the central nervous system (tractotomy) or axotomy (//)of peripheral motor and sensory axons. The different cell types displaying clusterin upregulation are symbolized in the following way: neurons (O), astrocytes (▲), oligodendrocytes (•), axon stumps (*).

Fig. 8.1. Cartoon summarizing the localization of clusterin upregulation following various types of injury, brain contusion (arrow), lesion (//) of a pathway in the central nervous system (tractotomy) or axotomy (//)of peripheral motor and sensory axons. The different cell types displaying clusterin upregulation are symbolized in the following way: neurons (O), astrocytes (▲), oligodendrocytes (•), axon stumps (*).

neurons, and a possible increase in perineuronal labeling is difficult to assess. Taken together, these findings are compatible with the conclusion that astrocytic clusterin is upregulated, but not exceeding the general upregulation associated with the axotomy-in-duced astrocytic response.

Was this article helpful?

0 0
Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Post a comment