Ma. Walter et al., FIBROBLAST GROWTH FACTOR-INDUCED MOTOR END-PLATE REGENERATION IN ATROPHIC MUSCLE, Archives of otolaryngology, head & neck surgery, 122(4), 1996, pp. 425-430
Objective: To determine whether fibroblast growth factor 1 implanted w
ith viable nerve into atrophic muscle will stimulate formation of func
tional, acetylcholine-producing motor end plates. Design: Twelve male
Lewis rats underwent predenervation of the hamstring muscle 8 weeks be
fore implantation of the nerve at a site distant from the original mot
or end plate. Six animals underwent implantation of the tagged nerve e
nding into atrophic muscle with 50 mu g of fibroblast growth factor 1
in a fibrin adhesive carrier (group 1). Three animals underwent implan
tation with nerve, fibrin adhesive, and no fibroblast growth factor 1
(group 2), and three animals underwent implantation with fibroblast gr
owth factor 1 and fibrin adhesive with no nerve (group 3). Animals wer
e killed 9 weeks after implantation and nerve and muscle specimens wer
e harvested. Main Outcome Measures: Histoenzymologic methods for acety
lcholinesterase and silver impregnation of nerve fibers were performed
9 weeks after fibroblast growth factor l-fibrin adhesive implantation
. Variables included the number of motor end plates per high-power fie
ld and motor end plate length. Results: Robust axonal sprouting and fo
rmation of multiple motor end plates were found arborized in serial fa
shion equidistant around the implanted nerve ending. Rare extrasynapti
c staining occurred. End plate lengths were significantly shorter in t
he fibroblast growth factor 1-treated muscles (group 1) than in the sp
ecimens without fibroblast growth factor 1 (group 2) (31.2 vs 58.5 mu
m; P>.001, paired t test). The arborization of motor end plates, rare
extrasynaptic staining, and shorter end plate lengths seen in group 1
were all consistent with mature motor end plates. Controls (group 3) d
isplayed limited motor end plate formation and extensive extrasynaptic
staining typical of denervation.Conclusions: This study presents enco
uraging evidence that fibroblast growth factor 1 with fibrin adhesive
carrier can facilitate the reinnervation of atrophied muscle by enhanc
ing the formation or revitalization of motor end plates. Future studie
s will address muscle function and use of different carrier materials.