Effects of Unilateral Electroacupuncture on Bilateral Proprioception in a Unilateral Anterior Cruciate Ligament Injury Model

BACKGROUND: Anterior cruciate ligament (ACL) injury can cause knee proprioception degeneration, on which the electroacupuncture (EA) treatment has a definite effect. However, it is still not clear whether conducting EA intervention on the injured side can promote bilateral proprioception recovery. MATERIAL/METHODS: We randomly selected 6 of 9 normal cynomolgus monkeys to develop unilateral ACL injury models via arthroscopy. All knees were divided into 5 groups: the normal control (NC) group, injured side of blank model (ISBM) group, contralateral side of blank model (CSBM) group, injured side of EA (ISE) group, and contralateral side of EA (CSE) group. Ten days after modeling, the monkeys in the EA group were treated with EA daily for 6 weeks at the acupoints. At 6 weeks, the 5 groups were examined by electrophysiology (SEPs and MCV). The ACL was separated to conduct the gold chloride staining for morphology observation and count the number of total and variant proprioceptors. RESULTS: At 6 weeks, the latent period of the SEPs and MCV and the number of variant proprioceptors in the blank model group and the EA group were increased compared with the NC group, while the amplitude and the number of total proprioceptors were decreased. The changes in the ISBM and CSBM group were more remarkable than in the ISE and CSE group. All differences were statistically significant (P<0.05). CONCLUSIONS: Unilateral ACL injury leads to bilateral proprioception degeneration, and the unilateral knee EA intervention can aid bilateral proprioception recovery.