Maresin2通过促进小胶质细胞M2极化治疗痛性糖尿病周围神经病变的机制研究 *

Effect of Maresin2 on Mechanical Pain Threshold in Mice with Painful Diabetic Peripheral Neuropathy and Its Potential Mechanism *

摘要:

目的：探讨Maresin2(MaR2)对痛性糖尿病周围神经病变（Painful Diabetic Peripheral Neuropathy, PDPN）小鼠模型机械痛阈的影响及其可能机制。方法：使用简单随机抽样方法将小鼠分为4组：溶剂对照组（Vehicle）、模型组（PDPN）、模型+MaR2-10ng组（MaR2-10ng）、模型+MaR2-100ng组（MaR2-100ng），每组8只。采用腹腔注射链脲佐菌素（streptozotocin,STZ）构建小鼠PDPN模型，并通过血糖升高及机械性痛觉过敏确认模型的成功建立。于造模前、造模后第7、14、21天，以及第22–28天鞘内给药后4小时，检测小鼠50%机械刺激缩足反射阈值（50% Mechanical withdrawal threshold, 50% MWT）。采用免疫荧光染色（IF）检测小胶质细胞激活指标Iba1；采用Western blot检测脊髓组织中Iba1、CD68、Arg1、iNOS的蛋白表达；流式细胞术检测M1/M2型小胶质细胞极化比例，采用RT-qPCR、ELISA检测神经炎症标志物（如 IL-1β、IL-6、TNF-α、IL-10）。结果：与Vehicle组相比，PDPN组小鼠出现显著机械性痛觉过敏，脊髓背角小胶质细胞显著激活，M1型小胶质细胞比例显著升高，而M2型小胶质细胞比例下降。与PDPN组相比，鞘内注射MaR2（10或100 ng）以剂量依赖性降低机械性痛觉过敏，降低脊髓背角小胶质细胞激活程度，降低脊髓小胶质细胞M1型细胞比例，增加M2型比例，减少脊髓促炎因子（IL-1β、IL-6、TNF-α）的表达、增加抗炎因子（IL-10）的表达。结论：鞘内注射MaR2对PDPN小鼠具有显著的镇痛作用，其机制可能与调节脊髓背角小胶质细胞极化状态、改善神经炎症有关。

Abstract:

Objective: To investigate the effect of maresin2 (MaR2) on mechanical pain threshold and its underlying mechanism in a mouse model of Painful Diabetic Peripheral Neuropathy (PDPN). Methods: Mice were randomly divided into four groups: Vehicle group (Vehicle), Painful Diabetic Peripheral Neuropathy model group (PDPN), PDPN + MaR2-10 ng group (MaR2-10ng), and PDPN +MaR2-100 ng group (MaR2-100ng), with 8 mice per group. A Painful Diabetic Peripheral Neuropathy (PDPN) model was induced by intraperitoneal injection of streptozotocin (STZ), and the successful establishment of the model was confirmed through elevated blood glucose levels and mechanical hyperalgesia. 50% MWT was assessed prior to model establishment, on days 7, 14, and 21 post-modeling, and at 4 hours after the daily intrathecal administration of MaR2 on days 22-28. The expression of Iba1 were detected by Immunofluorescence staining. The protein expression levels of Iba1, CD68, Arg1, iNOS were assessed by Western blot. Percentages of M1 microglia phenotype and M2 microglia phenotype were detected by flow cytometry. Furthermore, the expression levels of neuroinflammatory markers (including IL-1β, IL-6, TNF-α, and IL-10) were quantified by RT-qPCR and ELISA. Results: Compared with the Vehicle group, the PDPN group developed significant mechanical allodynia, along with marked microglial activation in the spinal dorsal horn and a shift in microglial polarization toward the pro-inflammatory M1 phenotype and a concomitant reduction in the anti-inflammatory M2 phenotype. Compared to the PDPN group, intrathecal administration of MaR2 (10 or 100 ng) alleviated mechanical allodynia, suppressed microglial activation, promoted a shift from M1 to M2 polarization, and restored the balance of spinal cytokine expression by downregulating pro-inflammatory factors (IL-1β, IL-6, and TNF-α) while upregulating the anti-inflammatory cytokine IL-10. Conclusion: Intrathecal administration of Maresin2 produced significant analgesic effects in mice with PDPN, which may be associated with the regulation of microglial polarization and the improvement of neuroinflammation.