Protocatechuic acid as an inhibitor of the JNK/CXCL1/CXCR2 pathway relieves neuropathic pain in CCI rats.

Emerging evidence has shown that protocatechuic acid (PCA) has antioxidant and anti-inflammatory effects. It can alleviate the injury of sciatic nerve, while the mechanism of its therapeutic effect on neuralgia remains unknown . In vivo, chromium bowel ligation was used to establish a chronic constriction injury (CCI) rat model to induce sciatic nerve pain, then two doses of PCA were used to treat CCI rats. In vitro, 10 ng/mL TNF-α was used to stimulate glial satellite cells derived from the dorsal root ganglia (DRG) L4-L6 of the sciatic nerve to simulate sciatic nerve pain. PCA relieved mechanical allodynia and thermal hyperalgesia in CCI rats. CCK-8 assay revealed that PCA inhibited the proliferation of glial satellite cells induced by TNF-α. Moreover, ELISA demonstrated that PCA could improve the inflammatory response of rats caused by CCI and cells induced by TNF-α. Next, RT-qPCR and Western blot assays testified that PCA blocked the c-Jun N-terminal kinase/the chemokine ligand 1/CXC chemokine receptor 2 (JNK/CXCL1/CXCR2) pathway by inhibiting CXCL1 levels in cells induced by TNF-α and DRG of CCI rats. In conclusion, PCA can alleviate neuropathic pain of CCI rats, improve oxidative stress by inhibiting the JNK/CXCL1/CXCR2 signaling pathway, which provides a new perspective for the treatment of neuropathic pain caused by CCI.

[Study on the nonlinear Raman lidar monitoring the CO2 gas].

It is a new skill to use SRS rays as emitting waves for the lidar monitoring CO2 gas, and the nonlinear Raman lidar based on the SRS process was devised. The third harmonic Nd: YAG laser wave (354.7 nm) was injected into the Raman cells filled with higher pressure gases, CO2 and N2. The first Stokes (S1) line 371.66 nm (CO2) and 386.7 nm (N2) were generated by stimulated Raman scattering. The variable S1 energy was measured by changing the gas pressure in the Raman cell andthe Nd:YAG laser system output energy. The optimum pressures of the CO2 and N2 in the Raman cell were achieved. Moreover, the principles of this physical process were put forward. This skill has been applied to the lidar for monitoring the CO2 gas.