A MODIFICATION OF THE CHRONIC CONSTRICTION INJURY MODEL OF NEUROPATHIC PAIN: SILK USAGE INSTEAD OF CHROMIC CATGUT

Abstract

Objective: In the chronic constriction injury (CCI) neuropathic pain rat model, usage of chromic catgut causes intense neuroinflammation and also undesirable conditions such as autotomy. This causes difficulties in the application and interpretation of pain behaviour tests. In this study, it was aimed to investigate the suitability of the use of surgical silk as a suture material in the CCI model, based on behavioural tests and certain biomarkers. Material and Methods: CCI model was created by loosely ligating the right sciatic nerves of rats with surgical silk. Tactile allodynia, thermal and mechanical hyperalgesia were evaluated on the 2nd, 7th, 14th, 21st and 29th postoperative days. Expressions of glial fibrillary acidic protein (GFAP), signal transducer and transcription activator 3 (STAT3) and its phosphorylated form (p-STAT3) were evaluated from the spinal cord tissue by western blotting technique. Results: Sciatic nerve-ligated rats did not lose weight but gained weight on days 14, 21, and 29 like control rats. Statistically significant decreases were found in pain thresholds in three different pain tests after the operation. The decrease in the pain threshold was accompanied by a statistically significant increase in GFAP protein expression in the spinal cord on days 2 and 14 simultaneously. No statistically significant difference was found in the expression of STAT3 or p-STAT3 protein in the spinal cord at any time. Conclusion: The absence of weight loss and autotomy expected from the classical CCI model, the reversal of the decrease in the pain threshold, the concomittant increase in GFAP protein expression in the spinal cord, and the absence of change in STAT3 and p-STAT3 expression in our study suggest that the model we created by tying 3 loose silk knots on the sciatic nerve has a milder course of neuroinflammation.

Keywords

• Allodynia
• hyperalgesia
• catgut
• silk

Nöropatik Ağrı Kronik Sıkıştırma Hasarı Modelinde Bir Değişiklik: Krome Katgüt Yerine İpek Kullanımı

Abstract

Amaç: Kronik konstriksiyon yaralanması (KKY) nöropatik ağrı sıçan modelinde krome katgüt kullanımı yoğun nöroinflamasyona ve ototomi gibi istenmeyen durumlara neden olmaktadır. Bu durum ağrı davranış testlerinin uygulanmasında ve yorumlanmasında zorluklara neden olmaktadır. Bu çalışmada, KKY modelinde cerrahi ipeğin dikiş materyali olarak kullanımının uygunluğunun davranış testleri ve bazı biyobelirteçlere dayalı olarak araştırılması amaçlandı. Gereç ve Yöntemler: KKY modeli, sıçanların sağ siyatik sinirlerinin cerrahi ipek ile gevşek bir şekilde bağlanmasıyla oluşturuldu. Taktil allodini, termal ve mekanik hiperaljezi ameliyat sonrası 2., 7., 14., 21. ve 29. günlerde değerlendirildi. Glial fibriller asidik protein (GFAP), sinyal dönüştürücü ve transkripsiyon aktivatörü 3 (STAT3) ve bunun fosforile edilmiş formunun (p-STAT3) ekspresyonları, omurilik dokusundan western blot tekniği ile değerlendirildi. Bulgular: Siyatik siniri bağlanan sıçanlar kilo kaybetmedi, ancak kontrol sıçanları gibi 14, 21 ve 29. günlerde kilo aldı. Operasyon sonrası üç farklı ağrı testinde ağrı eşiklerinde istatistiksel olarak anlamlı düşüşler saptandı. Ağrı eşiğindeki azalmaya, aynı anda 2. ve 14. günlerde omurilikteki GFAP protein ekspresyonunda istatistiksel olarak anlamlı bir artış eşlik etti. Omurilikte STAT3 veya p-STAT3 proteininin ekspresyonunda herhangi bir zamanda istatistiksel olarak anlamlı bir fark bulunmadı. Sonuç: Klasik KKY modelinden beklenen kilo kaybı ve ototomi olmaması, ağrı eşiğindeki düşüşün tersine dönmesi, buna eşlik eden omurilikte GFAP protein ekspresyonunda artış, STAT3 ve p-STAT3 ekspresyonunda değişiklik olmaması çalışmamızda siyatik sinir üzerine 3 adet gevşek ipek düğüm atarak oluşturduğumuz modelde nöroinflamasyonun daha hafif seyrettiğini göstermektedir.

Keywords

• Allodini
• hiperaljezi
• katgüt
• ipek

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