RAT RED NUCLEAR TISSUE IL-21 AND ITS RECEPTORS ARE INVOLVED IN NEUROPATHIC INJURY AND NEUROPATHIC PAIN THROUGH NF-KB, MAPK, ERK AND JNK SIGNALING PATHWAYS

Shaokang Li^{1, *}, Bixin Tang¹, Jie Zhao¹, Xiaowen Cao¹, Zhiqing Liu¹, Sen Zhu¹, Yan Zhao¹, Weidong Liao², De’an Wang²

¹Gongli Hospital, Pudong New District, Shanghai 200135, PR China - ²People’s Hospital Group, Yantian District, Shenzhen 518083, PR China

Objective: To explore interleukin-21 (IL-21) and its receptor in rat red nuclear tissue through the nuclear transcription factor KB (NF-KB), mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), and c-Jun amino terminal kinase (JNK) signaling pathways involved in neuropathic pain. 

Methods: 36 clean healthy male SD rats were randomly selected and randomly divided into two groups: a sham operation group and model group, with 18 rats in each group, which were then subdivided into a medication group and non-medication group, with 9 rats in each group. A selective injury rat model was established; rats in the non-medication sham operation group and the non-medication model group were killed, and the IL-21, IL-21R, NF-KB, MAPK, ERK, and JNK expression levels were measured using Western blotting. The red nucleus tissues of rats in each non-medicine group were extracted and co-immunoprecipitation was performed using the IL-21 antibody to determine the expression level of IL-21R in each group. The IL-21 antibody was injected into the rat red nucleus to block the IL-21 signaling pathway, and the rats in each group were killed. The expression levels of NF-KB, MAPK, ERK, and JNK in the red nucleus of each group were measured using Western blotting. 

Results: Compared with the non-medication sham operation group, IL-21, IL-21R and NF-KB, MAPK, ERK, JNK expression levels in the non-medication model group were significantly increased (P<0.05). Under the same IL-21 expression level, compared with the non-medication sham operation group, the IL-21R expression level in the non-medication model group was significantly increased (P<0.05). Compared with the medication sham operation group, the expression levels of NF-KB, MAPK, ERK, and JNK of the red nucleus tissue in the medication model group were significantly reduced (P<0.05).

Conclusion: Rat red nuclear tissue IL-21 and its receptor IL-21R may participate in neuropathic pain through NF-KB, MAPK, ERK, and JNK signaling pathways.