Blockade of Toll-Like Receptors (TLR2, TLR4) Attenuates Pain and Potentiates Buprenorphine Analgesia in a Rat Neuropathic Pain Model

Figure 6

The influence of a single intrathecal administration of vehicle (“V”, sterile water), LPS-RS [20 μg/5 μL], or LPS-RS Ultrapure [“LPS-RSU’’ 20 μg/5 μL] on morphine (“M”, 2.5 μg/5 μL; (a), (c)) or buprenorphine (“B”, 2.5 μg/5 μL; (b), (d)) analgesia, as measured by von Frey’s test (mechanical allodynia; (a), (b)) and the cold plate test (thermal hyperalgesia; (c), (d)) 7 days after chronic constriction injury (CCI). The data are presented as the mean ± SEM. Intergroup differences were analyzed using one-way ANOVA followed by Bonferroni’s multiple comparisons test. , , and indicate significant differences compared with the vehicle-treated, CCI-exposed rats (V-CCI); , , and indicate significant differences between the LPS-RS and LPS-RS Ultrapure treated CCI-exposed groups after additional vehicle administration comparing to additional morphine or buprenorphine treated CCI-exposed groups; , , and indicate significant differences between vehicle-treated CCI-exposed groups after morphine or buprenorphine treatment and LPS-RS/LPS-RSU opioid treated CCI-exposed groups.