Tensiometric evaluation of the effect of lowfrequency electric stimulation on healing Achilles tendons in rats

Abstract Purpose: To evaluate the effects of low-frequency electric stimulation on biomechanics following surgical treatment of the Achilles tendon in rats. Methods: Forty-two rats were divided into two groups. One was given electric stimulation and the other was not. All were submitted to Achilles tenotomy and tenorrhaphy performed with a modified Kessler stitch. The experiment group underwent electric stimulation with 2 Hz, a nonpolarized current of 1 mA intensity for 14 days. The animals were euthanized at 2, 4 and 6 weeks for the biomechanical study. Results: The work performed, that is, the tendon’s capacity to absorb energy until rupture, was greater in the electrically stimulated group in the 2nd (p = 0.032) and in the 6th week (p = 0.010). The maximum tension, which is the capacity to support a load, was higher in the treated group in the 2nd (p = 0.030) and the 6th week (p = 024). These results indicate greater resistance of the electrically stimulated tendons. An analysis of the elastic module showed no differences. Conclusion: Low-frequency electric stimulation increased the resistance of the tendons at 2 and 6 weeks of evolution in rats.

摘要
研究目的：旨在评估低频电刺激对大鼠跟腱（Achilles tendon）术后生物力学特性的影响。
研究方法：将42只大鼠分为两组，一组接受低频电刺激干预，另一组作为对照。所有大鼠均接受跟腱切断术（tenotomy），并采用改良Kessler缝合法（modified Kessler stitch）完成腱缝合术（tenorrhaphy）。实验组采用2 Hz频率、1 mA强度的非极化电流进行电刺激，持续干预14天。分别于术后第2、4、6周处死大鼠，用于生物力学检测。
研究结果：电刺激组肌腱断裂前吸收能量的能力（即做功值）在术后第2周（p=0.032）和第6周（p=0.010）显著高于对照组；肌腱承受载荷的最大张力（即载荷承载能力）在术后第2周（p=0.030）和第6周（p=0.024）显著高于对照组。上述结果表明，接受电刺激的跟腱具有更强的抗断裂能力。对弹性模量（elastic module）的组间分析未发现显著差异。
研究结论：低频电刺激可提升大鼠跟腱术后2周及6周时的肌腱抗载荷能力。