电针调控TRPV4通道对膝骨关节炎模型小鼠软骨保护及提高疼痛敏感性作用研究OA

Objective To clarify the effects of electroacupuncture of knee-eye points on pain sensitivity of knee osteoarthritis(KOA)model mice and its mechanism.Methods Twenty SPF grade 6-month-old C57BL/6J male mice were selected and randomly divided into blank group,model group,acupuncture group 1,acupuncture group 2,5 mice in each group,and 5 SPF grade 6-month-old TRPV4 knockout male mice of the same strain were taken as acupuncture group 3.Except for the blank group,the rest of the mice were injected with 8 μL of collagenase preparation in the inner knee-eye of the left knee,and an equal amount of saline was injected in the inner knee-eye of the right knee,and the swelling of the knee joints was observed after 9 days.After 9 days,the knee joints were observed for redness and swelling and the degree of swelling was measured with vernier calipers.Acupuncture groups 1,2 and 3 were subjected to electroacupuncture intervention at the left inner and outer knee eye points,and the output pulses were set to be sparse and dense waves with intensities of 1 mA,0.3 mA and 1 mA(the arguments mentioned in the discussion),respectively,and frequencies of 2/10 Hz.Each time of electroacupuncture in all three groups,electroacupuncture intervention was carried out for 15 min,once a day for 5 days per week,with a rest period of 2 days,and the intervention was carried out for 2 weeks in total.The mice in the model group were given the same grasping and stockinette fixation for 15 min during the intervention as in the electroacupuncture group,and the mice in the blank group did not have any intervention.The pain thresholds of the right and left feet of the mice were recorded by the Von Frey test at the end of the treatment.Hematoxylin-eosin(HE)staining was used to observe the histomorphologic changes in the cartilage of the knee joint,and the Mankin score was used to evaluate the degree of cartilage degeneration.Results Compared with the control group,the bilateral paw pain thresholds in mice in acupuncture group 1 and acupuncture group 2 were significantly elevated(P<0.05),and both groups'pain thresholds were significantly higher than those before intervention,persisting until day 12 and day 5 after electroacupuncture intervention,respectively(P<0.05);Compared with the model group,the bilateral pain thresholds of mice in acupuncture group 1 and acupuncture group 2 were significantly increased(P<0.05),and the pain thresholds were significantly higher than those before intervention,persisting until the 12th and 5th days after electroacupuncture intervention,respectively(P<0.05);The cartilage surface was smooth,chondrocytes had normal morphology,and the Mankin scores were significantly reduced(P<0.05);Compared with acupuncture group 2,the bilateral pain thresholds in acupuncture group 1 were significantly higher(P<0.05);Compared with the acupuncture 3 group,the pain thresholds in both feet of mice in the acupuncture 1 and acupuncture 2 groups were significantly higher(P<0.05),and the pain thresholds were significantly higher than before the intervention,persisting until the 12th and 5th days after electroacupuncture,respectively(P<0.05),the cartilage surface was smooth,chondrocytes had normal morphology,and the Mankin scores were significantly reduced(P<0.05).Conclusion Electroacupuncture intervention significantly increased the pain threshold of both feet in KOA model mice,effectively improved pain sensitivity and had sustained and overall effects,and its mechanism was related to the modulation of TRPV4 channels to protect cartilage to reduce damage.