ABSTRACT
To investigate the role of spinal interleukin-6-Janus kinase 2 (IL-6-JAK2) signaling transduction pathway in regulating astrocytes activation during the maintenance of bone cancer pain (BCP). Methods: NCTC 2472 fibrosarcoma cells were injected into the femur marrow cavity in C3H/HeNCrlVr male mice to establish BCP model and they were replaced by the equal volume of α-MEM in the sham model. The paw withdrawal latency (PWL) was measured after inoculation of tumor cells. The lumbar enlargement of spinal cord (L3-L5) was isolated, and Real-time RT-PCR and Western blot were used to detect the expression of spinal glial fibrillary acidic protein (GFAP) and JAK2 mRNA and protein, respectively. The expression level of spinal GFAP mRNA indirectly reflect astrocytes activation level. Pain behaviors and spinal cord GFAP mRNA and protein expression were observed at the given time points after intrathecal administration of JAK2 antagonist AG-490. Results: The PWL at 10, 14, 21 d after operation in BCP model group were significantly shorter than that in the sham group (P<0.05); the spinal GFAP and JAK2 mRNA and protein levels were higher in the BCP model group in comparison to mice in the sham group (P<0.05); intrathecal injection of JAK2 agonist AG-490 (30 or 90 nmol) significantly alleviated PWL, and downregulated the expression of spinal GFAP mRNA and protein (P<0.05). Conclusion: The IL-6-JAK2 signaling pathway plays an important role in maintaining the BCP by regulating the expression of GFAP in the spinal cord. Intrathecal injection of AG-490 can reduce the BCP, and inhibit the activation of IL-6-JAK2 signaling pathway, which may be one of the mechanisms for spinal astrocyte activation.
Subject(s)
Animals , Male , Mice , Astrocytes , Pathology , Bone Neoplasms , Hyperalgesia , Drug Therapy , Injections, Spinal , Mice, Inbred C3H , Rats, Sprague-Dawley , Spinal Cord , Cell Biology , Pathology , TyrphostinsABSTRACT
Objective To investigate the effect of intrathecal injection of Tanshinone Ⅱ A on bone cancer pain behavior and spinal IL-1 β,IL-6,TNF-α expression.Methods According to the random number table method,84 C3H/HeNCrlVr male mice were divided into:(1) Tanshinone ⅡA 10 μg group:the tumor mice were treated by intrathecal administration (once daily on the days 14-20 after inoculation of tumor cells) with Tanshinone ⅡA 10 μg; (2)Tanshinone ⅡA 20 μg group:the tumor mice were treated with Tanshinone ⅡA 20 μg; (3)Tanshinone ⅡA 40 μg group:the tumor mice were treated with Tanshinone ⅡA 40 μg; (4) normal control group:the mice were given food and water ad libitum; (5) DMSO+Sham group:the sham mice were treated with the same volume of 5％DMSO; (6) Tanshinone ⅡA+Sham group:the sham mice were treated with Tanshinone ⅡA 40 μg; (7)DMSO+Tumor group:the tumor mice were treated with the same volume of 5％DMSO.The mice pain behaviors were assessed with the paw withdrawal thermal latency (PWTL) at the corresponding time points,then the mice were killed and the samples of spinal cord were detected by real-time PCR.Results The basic values of PWTL had no significant differences among all groups (P＞0.05).At day 14 after operation,no significant difference (P＞0.05) was found in the PWTL value between normal control group and the sham operation group.But in tumor group,the PWTL value was significantly lower than that of normal control group (P＜0.05).At day 21 after operation,the PWTL and the level of spinal IL-1 β,IL-6,TNF-α expression had no significant differences (P＞0.05) among normal control group,Tanshinone ⅡA+Sham group and DMSO+Sham group.The PWTL ((6.19± 1.26)s) in DMSO+ Tumor group was significantly lower than that of normal control group((16.01± 1.59)s) (P＜0.05),but the level of IL-1β,IL-6,TNF-α expression was higher than that of normal control group.Compared with the normal group,the PWTL ((9.83±1.26)s;(10.29±2.95) s) of Tanshinone Ⅱ A 20 μg and 40 μg group was higher,and the level of spinal IL-1β,IL-6,TNF-α expression was lower (P＜0.05).The PWTL and the levels of spinal IL-1β,IL-6,TNF-αexpression had no significant differences between Tanshinone ⅡA 10 μg group ((6.67 ± 0.96) s) and DMSO + Tumor group(P＞0.05).Conclusion Intrathecal injection of Tanshinone Ⅱ A plays a role in anti-cancer pain,and inhibition of spinal inflammatory cytokine release may be one of its mechanisms.
ABSTRACT
Objective To investigate effects of metabotropic glutamate receptor subtype 5 (mGluR5) antagonist MTEP on the nociceptive behavior and the expression of glial fibrillary acidic protein (GFAP) in spinal cord associated with bone cancer pain. Methods C3H/HeNCrlVr 60 male mice were randomly divided into 5 groups: ( 1 ) normal control group: the mice were given food and water ad libitum; ( 2 ) MTEP + Tumor group: the mice were treated by intrathecal gdministration ( once daily on the days 14 ～20 after inoculation of tumor cells)with MTEP (150 nmol); (3) physiological saline + Tumor group:the tumor mice were treated with the same volume of physiological saline; (4) MTEP + Sham group: the sham mice were treated with the same dose of MTEP;(5) physiological saline + Sham group: the sham mice were treated with the same volume of physiological saline.the mice pain behaviors were assessed with the paw withdrawal thermal latency (PWTL) at the corresponding time points, then the mice were killed and the samples of spinal cord were used to real-time PCR and western blot detection of GFAP mRNA and protein expression. Results The basic values of PWTL had no significant differences among all groups (P＜0.05). At day 14 after operation,no significant difference was found in the PWTL value between normal control group and the sham operation group. But in tumor group, the PWTL value was significantly lower than in the normal control group (P＜ 0.05 ). At day 21 after operation,the PWTL and the level of GFAP expression in the spinal cord had no significant differences among normal control group, MTEP + Sham group and physiological saline + Sham group (P ＞ 0.05 ); the PWTL ( (6. 18 ± 1.29 ) s) in physiological saline + Tumor group was significantly lower than in normal control group ( ( 15.91 ± 1.65 )s), physiological saline + Sham group ( ( 16.57 ± 1.86) s) and MTEP + Sham group ( ( 17.05 ± 2.43 ) s) (P ＜ 0.05 ), but the level of GFAP expression was higher than in the above three groups. In MTEP +Tumor group ,the PWTL (9.39 ± 1.94s) was higher than in physiological saline + Tumor group, and the level of GFAP expression was lower than in physiological saline +Tumor group (P ＜ 0.05 ). Conclusion Inhibiting spinal activation of astrocytes may be one of the MTEP anticancer pain mechanisms.
ABSTRACT
Objective To investigate the role of Ca2+/calmodulin-dependent protein kinase Ⅱ on pain behavior in a mouse model of bone cancer pain. Methods 40 male C3H/HeN mice were divided randomly into 5 groups:sham group (S group, n=8) ,control group (C group, n=8) and KN93 treat group (T1, n=8;T2, n=8;T3, n = 8 ). Group C and T were induced mouse models of bone cancer pain by intra-left-femur inoculations of osteolytic NCTC2472 cells while group S were injected only α-MEM. On the 14 d after inoculations,group S and C received intrathecal injection of 20% DMSO 5 μl . While group T1, T2, T3 received intrathecal injection of KN93 15nmol,30nmol,60nmol which dissolved in 5 μl 20% DMSO respectively. Mice received pain behavior tests including quantification of spontaneous flinches, paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) before and at 0.5 h,2 h,4 h,8 h after administration. Results Treatment with KN93(15 nmol) have no effect on bone cancer pain,while treatment with KN93(30 nmol,60 nmol) can dose-dependently reverse quantification of spontaneous flinches, mechanical allodynia and thermal hyperalgesia which were induced by bone cancer pain, At 0. 5h after administration, the quantification of spontaneous flinches of the two groups ( (7.25 + 1.49 ), (4. 12 + 1.36 ) ) were decreased when compared with control group ( 11.62 + 1.92 ),PWMT((1.28 +0.14)g;(1.75 +0.46)g),PWTL((14.64 +2.12) s; (16.85 + 1.61)s)were increased when compared with control group ( (0.47 + 0. 16) g, ( 11.32 + 1.68 ) s) (P ＜ 0.05 ＝. The effect lasts for at least 4 h and disappears at 8 h. Conclusion CaMK Ⅱ may play an important role in the mechanism of bone cancer pain. Intrathecal KN93 injection can effectively attenuated bone cancer pain.
ABSTRACT
Objective To investigate the effect of intraperitoneal injection of thalidomide on pain behaviors in a mouse model of bone cancer pain. Methods 36 male C3H/HeJ mice were divided randomly into tumor group (n= 18) and sham group (n= 18) ,six mice from each group were chosen to examine the time course of changes in behavior after tumor cells inoculated to the bone. 2 × 105 osteosarcoma NCTC 2472 cells were implanted into the intramedullary space of the right femurs of mice to induce ongoing bone cancer related pain behaviors. The sham group was inoculated by α-MEM without any cells. On the day before inoculation,the tumor mice were divided randomly into tumor + thalidomide group and tumor + vehicle group. The sham group mice were further divided randomly into sham + thalidomide group and sham + vehicle group. Pain ethology indexes such as paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were observed on 1 d before inoculation and on 3 d ,5 d ,7 d, 10 d, 14 d after inoculation. Results ( 1 ) At day 7 after the operation, compared with sham mice ( 1. 70 ± 0. 33 ) g, PWMT of tumor mice decreased to ( 1.07 ± 0. 30) g (P ＜ 0. 05 ). At day 10, PWTL shortened to ( 12.60 ± 1.69 ) s (P ＜ 0. 05 ) compared with sham mice ( 17.70 ± 1.54 ) s. And the pain behaviors of tumor mice were aggravated along with the development of cancer pain. (2) At day 7 after the operation, compared with tumor + vehicle group ( 1. 07 ± 0.39 ) g, PWMT of tumor + thalidomide group increased to ( 1. 53 ± 0. 39 ) g (P ＜0.05). At day 10, PWTL extended to ( 16.48 ± 1.13 ) s compared with sham mice ( 12.64 ± 1. 56) s (P ＜0. 05 ). Conclusion Intraperitoneal injection of thalidomide can efficiently relieve mechanical hyperalgia and thermal hyperalgia in a mouse model of bone cancer pain.