Effect of An-pressing manipulation on post-stroke muscle spasticity in rats and its mechanism study

Objective To explore the mechanism of An-pressing manipulation in improving post-stroke muscle spasticity, by observing the changes of γ-aminobutyric acid (GABA) and glycine (Gly) in plasma and gray matter of L 1 -L 3 spinal cord anterior horn in post-stroke rats with muscle spasticity after An-pressing manipulation intervention. Methods Ten of 80 adult male Sprague-Dawley (SD) rats were randomly selected as the blank group, and the remaining 70 were used for modeling. The middle cerebral artery occlusion (MCAO) rat model was established by insertion suture occlusion method in the left external carotid artery. Thirty rats with a Longa neurological score of 2-3 points and a modified Ashworth spasticity scale score of 1 − , 1 + , or 2 were included in the experiment. Using the random number table method, the 30 successfully modeled rats were randomly divided into a model group, an An-pressing tendon group and an An-pressing muscle belly group. Two days after modeling, rats in the An-pressing tendon group and An-pressing muscle belly group received An-pressing manipulation on the tendon and belly of quadriceps femoris muscle respectively, with the pressure of (350±50) g and the frequency of 5 s/time, 15 min per session, once a day for 5 continuous days. After the 5th treatment, the tension of the rat quadriceps femoris muscle was evaluated using the modified Ashworth spasticity scale. The Gly levels in rat plasma and L 1 -L 3 segments of spinal cord were determined by enzyme-linked immunosorbent assay (ELISA). The GABA levels in rat plasma and L 1 -L 3 segments of spinal cord were measured by high performance liquid chromatography (HPLC). Results The decrease in rat muscle tension scored by the modified Ashworth spasticity scale in the An-pressing tendon group was more significant than that in the An-pressing muscle belly group ( P <0.01); the increases in Gly and GABA levels in the rat plasma and L 1 -L 3 segments of spinal cord were more significant in the An-pressing tendon group than those in the An-pressing muscle belly group (all P <0.01). Conclusion Based on the theory of ‘anti-stretch reflex’ of tendon organs, the use of An-pressing manipulation to induce the ‘anti-stretch reflex’ by stimulating the tendon organs can improve the muscle spasticity of rats, which is better than An-pressing the muscle belly. Increased levels of Gly and GABA in rat plasma and L 1 -L 3 segments of spinal cord may be one mechanism of An-pressing manipulation to improve muscle spasticity by stimulating tendon organs.