RESUMEN
Using a specific antibody (SMI 31), the state of phosphorylation of high and medium molecular weight neurofilaments (NF-H and NF-M) was studied in 22 leprous and four nonleprous human peripheral nerves by means of immunohistochemistry, sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE) and Western immunoblot (WB). The results thus obtained were compared with morphological changes in the respective nerves studied through light and electron microscopy. Many of the leprous nerves showing minimal pathology revealed lack of or weak staining with SMI 31, denoting dephosphorylation. Remyelinated fibres stained intensely with SMI 31 antibody. The WB analysis of Triton X-100 insoluble cytoskeletal preparation showed absence of regular SMI 31 reactive bands corresponding to 200 and 150 kDa molecular weight (NF-H and NF-M, respectively) in 10 nerves. Three of the 10 nerves revealed presence of NF protein bands in SDS-PAGE but not in WB. Presence of additional protein band (following NF-M) was seen in four nerves. Two nerves revealed NF-H band but not NF-M band and one nerve showed trace positivity. In the remaining five nerves presence of all the three NF bands was seen. Thus, 77.3% (17/22) of human leprous nerves studied showed abnormal phosphorylation of NF protein(s). The ultrastructural study showed abnormal compaction and arraying of NF at the periphery of the axons in the fibres with altered axon to myelin thickness ratio (atrophied fibres) as well as at the Schmidt-Lantermann (S-L) cleft region. Such NF changes were more pronounced in the severely atrophied axons suggesting a direct correlation. The observed well-spaced NF in the remyelinated fibres under ultrastructural study was in keeping with both intense SMI 31 staining and presence of NF triplet bands seen in WBs in four of leprous nerves that showed a large number of regenerating fibres suggesting reversal of changes with regeneration. Findings in the present study suggest that atrophy, that is, the reduction in axonal calibre and paranodal demyelination, seen in leprous nerves may result from dephosphorylation of NF-H and NF-M proteins.
Asunto(s)
Humanos , Atrofia , Axones , Citoesqueleto , Enfermedad de Alzheimer , Enfermedades Desmielinizantes , Electroforesis en Gel de Poliacrilamida , Esclerosis Amiotrófica Lateral , Fibras Nerviosas , Fosforilación , Lepra , Inmunohistoquímica , Adhesión en Parafina , Neuronas , Proteínas de Neurofilamentos , Western BlottingAsunto(s)
Anticuerpos Monoclonales , Antígenos Bacterianos/análisis , Lepra/inmunología , Lepra/microbiología , Lepra/patología , Mycobacterium leprae/inmunología , Mycobacterium leprae/aislamiento & purificación , Nervios Periféricos/inmunología , Nervios Periféricos/microbiología , Nervios Periféricos/patología , Técnicas para InmunoenzimasRESUMEN
A total of six index finger branch of the radial cutaneous (IRC) nerves from three BL, two BB and one BT cases of leprosy, with less than 6 months history of disease were subjected for nerve conduction velocity (NCV) studies followed by biopsy. The biopsy was divided into three parts and subjected for light microscopy quantitative histology, electron-microscopy and fibre tease studies. The nerves revealed a slight reduction in NCV and a varying degree of segmental demyelination ranging from 10% to 35%. The earliest changes observed were the thickening and proliferation of Schwann cell processes of the unmyelinated fibres and degeneration of their axons regardless of the type of leprosy. A total of 35 contacts from 20 families of lepromatous index cases were screened clinically. All of them were subjected for nerve conduction velocity (NCV) studies of both left and right index branch of the radial cutaneous (IRC) nerve. Fifteen of these nerves were biopsied. Out of 15 IRC nerves biopsied 10 had slightly reduced average NCV values and 5 were normal. Four nerves out of 10 where average NCV was reduced and 1 nerve out of 5 where NCV was normal showed significant ultrastructural changes and higher percentage of segmental demyelination (10%--13%). There was a striking similarity between the changes seen in the IRC nerves of early cases of leprosy and of contacts.
Asunto(s)
Masculino , Femenino , Adolescente , Adulto , Niño , Humanos , Persona de Mediana Edad , Conducción Nerviosa , Células de Schwann/ultraestructura , Dedos/irrigación sanguínea , Degeneración Nerviosa , Factores de Tiempo , Fibras Nerviosas/ultraestructura , Lepra/diagnóstico , Lepra/genética , Lepra/patología , Nervio Radial/patología , Nervio Radial/ultraestructura , Piel/irrigación sanguíneaRESUMEN
A teased fibre technique was used to study 19 biopsies of the index finger branch of the radial cutaneous nerve of leprosy patients and contacts. These were compared with four normal nerves. Five nerves were from patients with preclinical nerve lesions, five from leprosy patients with minimal sensory nerve impairment, and five from contacts of lepromatous leprosy. The extent of demyelination in preclinical nerve lesions in leprosy and in contacts of leprosy is recorded. The usefulness of nerve conduction velocity studies in early leprosy patients and in contacts is discussed.