Fibre type specific expression of Leu19-antigen and N-CAM in skeletal muscle in various stages after experimental denervation.
Leu-19 antigen, which seems to be identical with neural cell adhesion molecule (N-CAM), plays a major role in the innervation of muscle cells, and in adult muscle appears after denervation and during regeneration of muscle fibres, where it acts as part of a signalling system increasing the probability of re-innervation. This combined enzyme-histochemical and immunohistochemical study examined whether this signalling process was regulated in a uniform or differential pattern for type 1 and type 2 muscle fibres. The subscapular nerve of 18 rabbits was transsected with subsequent complete denervation of the supraspinatus muscle. Leu-19 and N-CAM immunohistochemistry was performed 2 to 64 days after surgery. Whereas in normal muscle there are virtually no Leu-19/N-CAM positive muscle fibres; from day 2 after denervation an increasing proportion of fibres expressed Leu-19/N-CAM, prior to any neurogenic atrophy. In the early stage of denervation Leu19/N-CAM expression was confined to type 1 fibres. After 11 days nearly all fibres were Leu19/N-CAM positive irrespective of their fibre type. Sixty-four days after denervation type 1 fibres became Leu19/N-CAM negative, while atrophic type 2 fibres showed intensive staining. Thus, expression of Leu-19 antigenicity is differently regulated in both fibre types.
Müller-Felber
W
W
Friedrich Baur Institut, Ludwig Maximilians Universität, Munich, Germany.
Küllmer
K
K
Fischer
P
P
Reimers
C D
CD
Wagner
S
S
Harland
U
U
Schmidt-Achert
M
M
Pongratz
D
D
D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D019002:CD56 Antigen; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis*; D008297:Male; D009121:Muscle Denervation; D009132:Muscles / Q000737:chemistry* / Q000473:pathology; D011817:Rabbits; D013997:Time Factors
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D019002:CD56 Antigen; D015816:Cell Adhesion Molecules, Neuronal