The effects of extracorporeal shock waves on carrageenan-induced Achilles tendinitis in rats: a biomechanical and histological analysis

Abstract

Objective: The aim of this study was to investigate the influence of low-dose extracorporeal shock waves (ESW) on the healing potential of Achilles tendinitis in the rat.
Methods: The 36 adult Sprague-Dawley rats used in this study were randomly divided into four groups. Group A (n=10) were injected with carrageenan, Group B (n=10) were injected with carrageenan and received ESW, Group C (n=10) received ESW only, and Group D (n=6) was a sham group. Rats were injected with 10 microliters of 3% carrageenan or a saline solution eight times during a one-week period with a subcutaneous needle. One week following the final injection, ESW was applied at a rate of 500 impulses in 5 minutes at 2 bars (comparative to 0.09 mJ/mm2) to rats in Groups B and C. Rats were sacrificed three weeks later. Tensile strength, inflammation, and vascularity and collagen density were measured.
Results: Failure of the tendon ultimate loads was significantly lower in the study groups than in the control group (p<0.05). Collagen fiber density was higher in the control group than in the other groups (p=0.59). No other histological differences were found.
Conclusion: Low-dose ESW has a negative effect on tendon tensile strength in this animal model.

Keywords

• Achilles tendinitis
• biomechanical analysis
• extracorporeal shock wave
• histological analysis
• rat

Sıçanlarda karragenan ile uyarılmış Aşil tendinitinde ekstrakorporeal şok dalgalarının etkinliği: Biyomekanik ve histolojik bir değerlendirme

Öz

Amaç: Bu çalışmanın amacı sıçanlarda Aşil tendinitinin iyileşmesinde düşük doz ekstrakorporeal şok dalgaların etkinliğinin incelenmesi idi. Çalışma planı: Çalışmada kullanılan 36 adet Sprague-Dawley sıçanı dört gruba ayrıldı. Grup A, karragenan enjekte edilen 10 sıçan, Grup B karragenan ve ekstrakorporeal şok dalga uygulanan 10 sıçan, Grup C ekstrakorporeal şok dalga uygulanan 10 sıçan ve Grup D kontrol grubu olarak 6 sıçandan oluşmaktaydı. Sıçanlara 10 mikrolitre %3’lük karragenan veya salin çözeltisi bir hafta içinde 8 defa subkutan iğne ile uygulandı. Son enjeksiyondan bir hafta sonra Grup B ve Grup C’deki sıçanlara 500 atım şok dalga 5 dakika süre ile 2 bar (yaklaşık 0.09 mJ/mm2) düzeyinde uygulandı. Sıçanlar üç hafta sonra sakrifiye edildi. Tendon gerim direnci, enflamasyon ve damarlanma ve kolajen yoğunlukları ölçüldü. Bulgular: Çalışma gruplarındaki tendon gerim direncinin kontrol grubuna göre anlamlı düzeyde daha düşük olduğu belirlendi (p<0.05). Kolajen liflerin yoğunluğu kontrol grubunda diğer gruplardan daha yüksekti (p=0.59). Histolojik başka bir farklılık belirlenmedi. Çıkarımlar: Bu hayvan modelinde düşük doz ekstrakorporeal şok dalgasının tendon gerim direncine olumsuz etkisi olduğu görülmüştür.

Anahtar Kelimeler

• Aşil tendiniti; biyomekanik inceleme; ekstrakorporeal şok dalga; histolojik inceleme; sıçan

References

1. Sharma P, Maffulli N. Biology of tendon injury: healing, modeling and remodeling. J Musculoskelet Neuronal Interact 2006;6:181-90.
2. Sharma P, Maffulli N. Tendon injury and tendinopathy: healing and repair. J Bone Joint Surg Am 2005;87:187-202. Xu ZH, Jiang Q, Chen DY, Xiong J, Shi DQ, Yuan T, et al. Extracorporeal shock wave treatment in nonunions of long bone fractures. Int Orthop 2009;33:789-93.
3. De Palma L, Gigante A, Rapali S. Physiopathology of the repair process of lesions of Achilles tendon. Foot Ankle Surg 2006;12:5-11.
4. Puddu G, Ippolito E, Postacchini F. A classification of Achilles tendon disease. Am J Sports Med 1976;4:145-50.
5. Warden SJ. Animal models for the study of tendinopathy. Br J Sports Med 2007;41:232-40.
6. Chung B, Wiley JP. Extracorporeal shockwave therapy: a review. Sports Med 2002;32:851-65.
7. Marsolais D, Côté CH, Frenette J. Neutrophils and macrophages accumulate sequentially following Achilles tendon injury. J Orthop Res 2001;19:1203-9.
8. Marsolais D, Duchesne E, Côté CH, Frenette J. Inflammatory cells do not decrease the ultimate tensile strength of intact tendons in vivo and in vitro: protective role of mechanical loading. J Appl Physiol 2007;102:11-7.

9. Tillander B, Franzén LE, Nilsson E, Norlin R. Carrageenaninduced subacromial bursitis caused changes in the rat’s rotator cuff. J Orthop Res 2001;19:441-7.
10. Di M. Biological properties of carrageenan. J Pharm Pharmacol 1972;24:89-102.
11. Wang CJ, Ko JY, Chen HS. Treatment of calcifying tendinitis of the shoulder with shock wave therapy. Clin Orthop Relat Res 2001;(387):83-9.
12. Wang CJ, Chen HS, Chen CE, Yang KD. Treatment of nonunions of long bone fractures with shock waves. Clin Orthop Relat Res 2001;(387):95-101.
13. Wang CJ, Huang HY, Pai CH. Shock wave-enhanced neovascularization at the tendon-bone junction: an experiment in dogs. J Foot Ankle Surg 2002;41:16-22.
14. Rompe JD, Kirkpatrick CJ, Küllmer K, Schwitalle M, Krischek O. Dose-related effects of shock waves on rabbit tendo Achillis. A sonographic and histological study. J Bone Joint Surg Br 1998;80:546-52.
15. Orhan Z, Cam K, Alper M, Ozturan K. The effects of extracorporeal shock waves on the rat Achilles tendon: is there a critical dose for tissue injury? Arch Orthop Trauma Surg 2004;124:631-5.
16. Orhan Z, Alper M, Akman Y, Yavuz O, Yalçiner A. An experimental study on the application of extracorporeal shock waves in the treatment of tendon injuries: preliminary report. J Orthop Sci 2001;6:566-70.
17. Rompe JD, Küllmer K, Vogel J, Eckardt A, Wahlmann U, Eysel P, et al. Extracorporeal shock-wave therapy. Experimental basis, clinical application. [Article in German]. Orthopade 1997;26: 215Chao YH, Tsuang YH, Sun JS, Chen LT, Chiang YF, Wang CC, et al. Effects of shock waves on tenocyte proliferation and extracellular matrix metabolism. Ultrasound Med Biol 2008; 34:841-52.
18. Leadbetter WB. Cell-matrix response in tendon injury. Clin Sports Med 1992;11:533-78.
19. Potenza AD. Tendon healing within the flexor digital sheath in the dog. J Bone Joint Surg Am 1962;44-A:49-64.
20. Nakama LH, King KB, Abrahamsson S, Rempel DM. Evidence of tendon microtears due to cyclical loading in an in vivo tendinopathy model. J Orthop Res 2005;23:1199-205.
21. Lake SP, Ansorge HL, Soslowsky LJ. Animal models of tendinopathy. Disabil Rehabil 2008;30:1530-41.
22. Chen YJ, Wang CJ, Yang KD, Kuo YR, Huang HC, Huang YT, et al. Extracorporeal shock waves promote healing of collagenase-induced Achilles tendinitis and increase TGFbeta1 and IGF-I expression. J Orthop Res 2004;22:854-61. Costa ML, Shepstone L, Donell ST, Thomas TL. Shock wave therapy for chronic Achilles tendon pain: a randomized placebo-controlled trial. Clin Orthop Relat Res 2005;(440):199-204. Hsu RW, Hsu WH, Tai CL, Lee KF. Effect of shock-wave therapy on patellar tendinopathy in a rabbit model. J Orthop Res 2004;22:221-7.