Evaluation of Immunohistochemical Expression of Collagen Type I and IV, Histopathological Changes, and Bacterial Isolates in Canine Pyometra

Abstract

Pyometra is a widespread and possibly fatal reproductive disease in intact female dogs but its pathogenesis, and the processes involved in tissue repair after infection, are not fully explained. The aim of the study was to clarify possible pathogenetic processes by analyzing clinical, histopathological and immunohistochemical activity of Collagen I and Collagen IV as well as bacteriological results of 6 healthy and 12 dogs with pyometra. These findings were confirmed through histopathological analysis with the help of the hematoxylin and eosin (H&E) staining, which revealed the presence of severe cystic endometrial hyperplasia, neoangiogenesis, Neutrophil-predominant inflammation, moderate hemorrhage, accumulation of inflammatory cells in endometrial glands and the presence of necrotic foci in glandular epithelium in pyometra cases, but mild or absent in healthy controls. Collagen I and Collagen IV expression underwent mild to moderate expression in controls but a significant increase in pyometra group, which revealed a high rate of extracellular matrix remodeling. Escherichia coli was microbiologically isolated in all (100) and Streptococcus spp. in two (16.7) cases. The strains of E. coli were different in their levels of multidrug resistance. Finally, this study demonstrates that the nature of pyometra is characterized by severe inflammation and uterine degeneration, high collagen expression, and the prevalence of multidrug-resistant bacterial infections. The research findings add to the knowledge of the pyometra pathogenesis, the criticality of antimicrobial resistance, and provide a valuable source of information for the veterinary literature on the condition.

Keywords

• Collagen
• Escherichia coli
• Immunohistochemistry
• Pyometra
• Streptococcus spp.

Supporting Institution

This research was financially supported by the Scientific Research Council of Dicle University (Project No: VETERİNER.22.004).

Project Number

1

Ethical Statement

For this research, an official statement from the Dicle University Local Ethics Committee was obtained on 30.10.2025 (Decision No. 01), indicating that this study is exempt from HADYEK ethical approval requirements.

Thanks

The authors express their gratitude to the Dicle University Scientific Research Projects Unit for financially supporting this study within the scope of Scientific Research Projects (BAP).

Köpek Pyometrasında Kollajen Tip I ve IV’ün İmmünohistokimyasal Ekspresyonu, Histopatolojik Değişiklikler ve Bakteriyel İzolatların Değerlendirilmesi

Abstract

Piyometra, kısırlaştırılmamış dişi köpeklerde yaygın ve muhtemelen ölümcül bir üreme hastalığıdır, ancak patogenezi ve enfeksiyon sonrası doku onarımında yer alan süreçler tam olarak açıklanmamıştır. Bu çalışmanın amacı, 6 sağlıklı ve 12 pyometra hastası köpeğin klinik, histopatolojik ve Kollajen I ve Kollajen IV'ün immünohistokimyasal aktivitesinin yanı sıra bakteriyolojik sonuçlarını analiz ederek olası patogenetik süreçleri açıklığa kavuşturmaktır. Bu bulgular, hematoksilen ve eozin (H&E) boyaması yardımıyla yapılan histopatolojik analizle doğrulandı; bu analiz, pyometra vakalarında şiddetli kistik endometrial hiperplazi, neovaskülarizasyon, nötrofilden baskın inflamasyon, orta derecede kanama, endometrial bezlerde inflamatuar hücre birikimi ve bez epitelyumunda nekrotik odakların varlığını ortaya koyarken, sağlıklı kontrollerde hafif veya yok denecek kadar azdı. Kollajen I ve Kollajen IV ekspresyonu kontrollerde hafif ila orta düzeyde iken, pyometra grubunda önemli bir artış gösterdi ve bu da yüksek oranda hücre dışı matris yeniden şekillenmesini ortaya koydu. Escherichia coli tüm vakalarda (100) ve Streptococcus spp. iki vakada (16,7) mikrobiyolojik olarak izole edildi. E. coli suşları, çoklu ilaç direnci düzeyleri bakımından farklılık gösterdi. Son olarak, bu çalışma, piyometranın doğasının şiddetli inflamasyon ve uterus dejenerasyonu, yüksek kolajen ekspresyonu ve çoklu ilaç dirençli bakteriyel enfeksiyonların yaygınlığını göstermektedir. Araştırma bulguları; piyometra patogenezi, antimikrobiyal direncin kritikliği hakkındaki bilgilere katkıda bulunmakta ve veteriner literatüründe bu durumla ilgili son derece değerli bir bilgi kaynağı haline gelmektedir.

Keywords

• Collajen
• Escherichia coli
• İmmünohistokimya
• Piyometra
• Streptococcus spp.

Supporting Institution

Bu araştırma, Dicle Üniversitesi Bilimsel Araştırma birimi tarafından mali olarak desteklenmiştir (Proje No: VETERİNER.22.004).

Project Number

1

Ethical Statement

Bu araştırma için, Dicle Üniversitesi Yerel Etik Kurulu'ndan 30.10.2025 tarihinde (Karar No. 01) resmi bir açıklama alınmış olup, bu çalışmanın HADYEK etik onay gerekliliklerinden muaf olduğu belirtilmiştir.

Thanks

Yazarlar, bu çalışmanın Bilimsel Araştırma Projeleri (BAP) kapsamında finansal olarak desteklenmesinden dolayı yazarlar Dicle Üniversitesi Bilimsel Araştırma projeleri birimine teşekkür ediyorlar.

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