Influence of chronic inflammation in peripheral target tissue on recovery of crushed nerve injury

An experimental study was performed to investigate the influence of chronic inflammation in peripheral target tissue on recovery of the sciatic nerve after crush injury. Thirty-four male Wistar rats, weighing 300-370 g were used. The sciatic nerve was crushed unilaterally with an aneurysm clip (250 gf; holding force; 5 min). One week before the operation, chronic inflammation, localized in the tibiotarsal joint of one hind limb, was produced by the intraarticular injection of complete Freund's adjuvant. The animals were divided into five groups, as follows: CIA (crush injury with ipsilateral arthritis), CCA (crush injury with contralateral arthritis), C (crush injury without arthritis), A (sham operation and ipsilateral arthritis), and S (sham operation without arthritis). Specimens for histological examination were taken from the nerve at a site 5 mm distal to the crush injury 4 weeks postoperatively. Histological study showed that the diameters of the axons in group CIA were significantly smaller than those in group CCA and those in group C. No significant differences were observed between group CCA and group C. In conclusion, peripheral nerve recovery after crush injury was suppressed by chronic inflammation in peripheral target tissue.