ABSTRACT
Objective: Histological and dynamic assessment to determine the effect of electroacupuncture on tendon repair in a rat model of Achilles tendon rupture. Methods: Sixty 12-week old male Wistar rats were used to prepare an Achilles tendon rupture model. The rats were randomly divided into an electroacupuncture group (EA group) and a control group. The EA group rats were restrained, and under mild anesthesia two acupuncture needles were inserted with the tip of one touching the ruptured tendon on the outer side, and the tip of the other touching it on the inner side. Using the needle on the inner side as the cathode and the needle on the outer side as the anode, electroacupuncture with intermittent direct current was performed (pulse width: 5 ms, stimulation frequency: 50 Hz, stimulation strength: 20 μA, stimulation time: 20 min). Electroacupuncture was performed every day from the day after model preparation until the days of assessment. Rats in the control group were retrained and mildly anesthetized only. Samples from the region of interest were taken 7 and 10 days after model preparation to assess tendon repair. Tissue imaging was performed, using HE staining to measure total cell count and immunohistochemical staining to measure the number of cells positive for TGF-β1 and b-FGF. Tension tests were also performed 10 days after model preparation to measure the maximum failure load of repaired tendon. Results: HE staining showed a significant difference between the assessment results on different days and between the two groups. A clear increase in the cell count was observed in the EA group (day 7: p<0.05, day 10: p<0.001). Immunostaining showed the strongest expression of both TGF-β1 and b-FGF in the EA group 7 days after model preparation, and other significant difference were observed (TGF-β1: day 7 EA group vs. day 10 EA group: p<0.001, vs. day 7 control group: p<0.0001, vs. day 10 control group: p<0.0001) (b-FGF: day 7 EA group vs. 10 EA group: p<0.001, vs. day 7 control group: p<0.0001, vs. 10 day control group: p<0.0001). Maximum failure load of repaired tendon 10 days after model preparation was significantly higher in the EA group (p<0.01). Discussion: Examination in the early stages after Achilles tendon rupture showed an increased cell count and increased expression of growth factors in the EA group, as well as increased tendon strength. These results indicate the beneficial action direct current electroacupuncture has on cell growth and growth factor expression during tendon repair, and suggest it also increases the dynamic strength of repaired tendon. Direct current electroacupuncture is thought to be possibly useful method for promoting tendon repair.
ABSTRACT
<B>Objective:</B> Histological and dynamic assessment to determine the effect of electroacupuncture on tendon repair in a rat model of Achilles tendon rupture.<br><B>Methods:</B> Sixty 12-week old male Wistar rats were used to prepare an Achilles tendon rupture model. The rats were randomly divided into an electroacupuncture group (EA group) and a control group. The EA group rats were restrained, and under mild anesthesia two acupuncture needles were inserted with the tip of one touching the ruptured tendon on the outer side, and the tip of the other touching it on the inner side. Using the needle on the inner side as the cathode and the needle on the outer side as the anode, electroacupuncture with intermittent direct current was performed (pulse width: 5 ms, stimulation frequency: 50 Hz, stimulation strength: 20 μA, stimulation time: 20 min). Electroacupuncture was performed every day from the day after model preparation until the days of assessment. Rats in the control group were retrained and mildly anesthetized only. Samples from the region of interest were taken 7 and 10 days after model preparation to assess tendon repair. Tissue imaging was performed, using HE staining to measure total cell count and immunohistochemical staining to measure the number of cells positive for TGF-<i>β</i>1 and b-FGF. Tension tests were also performed 10 days after model preparation to measure the maximum failure load of repaired tendon.<br><B>Results:</B> HE staining showed a significant difference between the assessment results on different days and between the two groups. A clear increase in the cell count was observed in the EA group (day 7: p<0.05, day 10: p<0.001). Immunostaining showed the strongest expression of both TGF-<i>β</i>1 and b-FGF inthe EA group 7 days after model preparation, and other significant difference were observed (TGF-<i>β</i>1: day 7 EA group vs. day 10 EA group: p<0.001, vs. day 7 control group: p<0.0001, vs. day 10 control group: p<0.0001) (b-FGF: day 7 EA group vs. 10 EA group: p<0.001, vs. day 7 control group: p<0.0001, vs. 10 day control group: p<0.0001). Maximum failure load of repaired tendon 10 days after model preparation was significantly higher in the EA group (p<0.01).<br><B>Discussion:</B> Examination in the early stages after Achilles tendon rupture showed an increased cell count and increased expression of growth factors in the EA group, as well as increased tendon strength. These results indicate the beneficial action direct current electroacupuncture has on cell growth and growth factor expression during tendon repair, and suggest it also increases the dynamic strength of repaired tendon. Direct current electroacupuncture is thought to be possibly useful method for promoting tendon repair.