The influence of fibronectin and laminin during Schwann cell migration and peripheral nerve regeneration through silicon chambers

Abstract

The ability of extracellular proteins to influence the regenerative process was examined in Sprague-Dawley rats. Silicon chambers, filled with sterile saline solutions of cytochrome-c, fibronectin, laminin, a combination of fibronectin and laminin, or nerve growth factor were surgically implanted between the severed ends of sciatic nerves to form gaps of 18 mm. Four months later, the various groups were examined to determine the success of regeneration. The incidence of cable formation that bridged the gap was similar in all groups. The group of animals that had implants containing the combination of fibronectin/laminin had increased numbers of myelinated axons in the regenerated segment within the chamber and in the distal sciatic tributary nerves. Horseradish peroxidase labelling demonstrated that increased numbers of sensory and motor neurons in the fibronectin/laminin group had regenerated axons across the gap into the distal tributaries of the sciatic nerve. The effect of the various agents on non-neuronal cells was measured by immunohistochemical staining with S-100 antibodies to determine the effects on Schwann cell migration. Silicon chambers, filled with sterile saline solutions of fibronectin, laminin, fibronectin/laminin, nerve growth factor, or cytochrome-c, were surgically implanted to form 5 mm gaps between severed sciatic nerve ends. Ten days later, Schwann cell migration into the bridging cables was examined in each group. Analysis revealed a greater influx of Schwann cells migrating into the regenerating segments in the fibronectin, the laminin, and the combination fibronectin/laminin groups compared to the control group (cytochrome-c).

Development of a Multiple-Lumen Nerve Cuff Utilizing Growth Stimulant Patterns for Controlled Regeneration

“…at 6 weeks and 4 months after implantation, respectively. They also found that a greater number of sensory and motor neurons was seen in the fibronectin-laminin group 6 weeks (Woolley et al, 1990) or 16 weeks (Bailey et al, 1993) (Fields et al, 1989).…”

“…Findings at 4 weeks demonstrate beneficial effects; 4 however, these appear not to be sustained over a longer period of time (8 mm gap, silicone rubber tubing, 1.2 mm I.D.). By contrast, the combination of fibronectin (FB) and laminin (LMN), two major glycoproteins associated with basal laminae, were shown to promote axonal regeneration continuously (Woolley et a!., 1990;Bailey et al, 1993;Tong et al, 1994). The FB/LMN solution has been shown to enhance regeneration through a single-lumen silicone chamber nerve cuff across 18 mm gaps in rats (Woolley et al, 1990;Bailey et al, 1993).…”

“…The basal lamina of the Schwann cells may provide a substratum for the regenerating axons to adhere and grow (Williams et al, 1983;Madison et al, 1988). Bailey et al (1993) have successfully used the combination of laminin and fibronectin to increase the influx of Schwann cells (1.37 mm^ of Schwann cell area in the laminin and fibronectin group compared to 0.68 mm^ in the cytochrome C group) migrating into the regenerating nerve segments which may promote axonal regeneration.…”

“…By contrast, the combination of fibronectin (FB) and laminin (LMN), two major glycoproteins associated with basal laminae, were shown to promote axonal regeneration continuously (Woolley et a!., 1990;Bailey et al, 1993;Tong et al, 1994). The FB/LMN solution has been shown to enhance regeneration through a single-lumen silicone chamber nerve cuff across 18 mm gaps in rats (Woolley et al, 1990;Bailey et al, 1993). Similarly, a gel containing collagen was filled in silicone tubes to increase the maximum successful nerve gap distance bridged up to 20 mm (Madison et al, 1988).…”

“…Horseradish peroxidase labeling showed that both sensory and motor neurons (see Table 1, pp. 328 in Madison et al (1988) (4) Mixture of laminin and fibronectin Woolley et al (1990) and Bailey et al (1993) have successfully used the combination of fibronectin (500 |i.g/ml in saline) and laminin (500 )ig/ml in saline) to enhance the regeneration of myelinated axons across a long nerve gap (18 mm) in silicone rubber tubes (1.4 mm I.D., 2.3 mm O.D.) at 6 weeks and 4 months after implantation, respectively.…”