富含亮氨酸重复激酶2在神经病理性疼痛大鼠痛敏中的作用及机制研究OA北大核心CSTPCD

Objective To study the effect of leucine rich repeat kinase 2(LRRK2)on pain sensitivity in neuro-pathic pain(NP)rats and explore its possible mechanism.Methods 48 SD rats were randomly divided into four groups:sham surgery(Sham),model,LRRK2 inhibitor(MLi-2),and LRRK2 inhibitor+p3 8 mitogen activated pro-tein kinase(MAPK)agonist(MLi-2+Anisomycin),with 12 rats in each group.The NP rat model was induced by chronic constriction injury(CCI)of the sciatic nerve.Intrathecal injection of MLi-2(1 mg/kg,10 μl)or Anisomy-cin(20 μmol/L,10 μl)was started from the 8th day after surgery,once a day for 7 consecutive days.Pain sensi-tivity tests were conducted before surgery(day 0)and on postoperative days 7 and 14,respectively.The changes in mechanical withdrawal threshold(MWT)and paw withdraw thermal latency(PWTL)were analyzed in each group of rats.ELISA was used to detect the levels of interleukin-1 β(IL-1β),IL-6 and tumor necrosis factor-α(TNF-α)in the dorsal horn of the rat spinal cord.Nissl staining was used to observe the pathological changes of neurons in rat spinal cord tissue.Immunofluorescence staining was used to observe the expression levels of ionized calcium-binding adapter molecule-1(Iba-1),a marker of microglia in the spinal cord of rats.Western blot was used to detect the protein expression levels of LRRK2,p-p38 mitogen activated protein kinase(MAPK),p38 MAPK,and Iba-1 in the dorsal horn of the rat spinal cord.Results Compared with the sham group,the model group showed a significant decrease in MWT and PWTL in the right hind limb of rats(P＜0.01).The levels of IL-1,IL-6,and TNF in the spi-nal dorsal horn tissue,as well as the expression levels of LRRK2,Iba-1 proteins and p-p38 MAPK/p38 MAPK pro-tein ratio significantly increased(P＜0.01).The proportion of Iba-1 positive cells in the spinal cord tissue signifi-cantly increased(P＜0.01),while Nissl bodies were significantly reduced(P＜0.01).Compared with the model group,the MLi-2 group showed a significant increase in MWT and PWTL in the right hind limb of rats(P＜0.01),a significant increase in Nissl bodies(P＜0.01),a significant decrease in the proportion of Iba-1 positive cells in the spinal cord tissue(P＜0.01),and a significant decrease in the levels of IL-1,IL-6,and TNF and the expression levels of LRRK2,Iba-1 proteins and p-p38 MAPK/p38 MAPK protein ratio(P＜0.01).However,Anisomychin in-tervention could activate the p38 MAPK signaling pathway and partially reverse the beneficial effects of MLi-2 on pain sensitivity and neuroinflammation in rats with neuropathic pain.Conclusion Inhibiting the expression of LRRK2 can alleviate pain sensitivity in NP rats induced by microglia activation mediated neuroinflammation,and its mechanism of action may be related to regulating the p38 MAPK signaling pathway.