Effects of Sciatic Neurectomy on Arthritis and Bone Loss in Rats with Collagen-Induced Arthritis

We investigated the effects of sciatic neurectomy on arthritis and bone mineral density (BMD) in 7-month-old female Sprague-Dawley rats with collagen-induced arthritis (CIA). After the animals obtained a uniform mean body weight, we divided them at random into 4 groups, and treated them with the following surgical manipulations: (i) sham group (n = 8), sham surgery; (ii) CIA group (n = 9), collagen sensitization and sham surgery; (iii) NTx group (n = 9), sciatic neurectomy and (iv) CIA + NTx group (n = 9), collagen sensitization and a sciatic neurectomy. Every 2 weeks up to 8 weeks after sensitization, the arthritis score for hind paw swelling was evaluated, and BMD of the cancellous and cortical bones in the proximal tibia was measured by peripheral quantitative computed tomography (pQCT). Both the hind paw swelling and arthritis score in the CIA + NTx group were significantly lower than those in the CIA group at 6 and 8 weeks after sensitization. There was no significant difference in the cancellous BMD between the CIA and CIA + NTx groups. The cortical BMD of the tibial metaphysis was significantly lower in the NTx and CIA + NTx groups than in the sham group at 4 and 8 weeks, and in the CIA + NTx group than in the CIA group at 4 weeks after sensitization. There was no significant difference between the CIA and sham groups as well as the CIA and CIA + NTx group at 8 weeks after sensitization. It was concluded that sciatic neurectomy suppressed the severity of arthritis, but did not affect the cancellous bone loss in adult CIA rats.