The effect of T0TNFSR or T0Z on the expression of TNFα, IL-1β, and p-p38 in the DRG. The non-replicating herpes simplex virus (HSV) vector T0TNFSR producing p55 TNFSR, and control vector T0Z were used. Rats received a repeated morphine dose 1 week after vectors. In the sham group, rats receive T0Z and a repeated dose of saline. At day 7, 1 hour after the last dose of morphine or saline, L4/5 DRGs were harvested, and the expression of TNFα, IL-1β and p-p38 was tested using Western blots. Repeated morphine admimistrations significantly induced upregulation of TNFα, IL-1β and p-p38. The expression of TNFα (A), IL-1β (B) and p-p38 (C) in morphine tolerance rats with T0TNFSR, was significantly lower than that in morphine tolerance rats with T0Z. # p<0.05 vs sham; * p < 0.05, n=4–6, ANOVA, post hoc comparisons using Fisher's PLSD test (StatViewJ 5.2).