[Effect of nerve growth factor on elderly degenerative knee osteoarthritis pain]

To explore effect of nerve growth factor (NGF) antibody on knee osteoarthritis (KOA) pain model was evaluated by in vitro model.

Thirty male SPF rats aged 28-week-old were divided into blank group (10 rats with anesthesia only). The other 20 rats were with monoiodoacetate (MIA) on the right knee joint to establish pain model of OA, and were randomly divided into control group (injected intraperitoneal injection of normal saline) and treatment group (injected anti-NGF) intraperitoneal after successful modeling, and 10 rats in each group. All rats were received retrograde injection of fluorogold (FG) into the right knee joint. Gait was assessed using catwalk gait analysis system before treatment, 1 and 2 weeks after treatment. Three weeks after treatment, right dorsal root ganglia (DRG) were excised on L4-L6 level, immunostained for calcitonin gene-related peptide (CGRP), and the number of DRGS was counted.

In terms of gait analysis using cat track system, duty cycle, swing speed and print area ratio in control and treatment group were significantly reduced compared with blank group (P<0.05). Compared with control group, duty cycle and swing speed of treatment group were significantly improved (P<0.05), and there was no significant difference in print area ratio between treatment group and blank group (P>0.05). The number of FG-labeled DRG neurons in control group was significantly higher than that in treatment group and blank group (P<0.05). The expression of CGRP in control group was up-regulated, and differences were statistically significant compared with treatment group (P<0.05).

Intraperitoneal injection of anti-NGF antibody inhibited gait injury and upregulation of CGRP in DRG neurons. The results suggest that anti-nerve growth factor therapy may be of value in treating knee pain. NGF may be an important target for the treatment of knee OA pain.