Fakülteler / Faculties

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A comparison of rat degloving injury models
(2017) Arpaci, Enver; Altun, Serdar; Orbay, Hakan; Ekinci, Mehmet; Cetinbas, Ahmet; Bal, Ali; Okur, Mehmet Ihsan; 28454780
Objective: Two different rat models for degloving injury were described in the literature. Our aim in this study is to compare these rat models to determine which one is more reliable and reproducible. Methods: We surgically induced degloving injury on tails and left hindlimbs of Wistar albino rats (n = 8), and sutured the avulsed tissues back in their original positions after a waiting period. We observed the changes in the avulsed flaps every other day for 10 days. At the end of follow-up period we evaluated the lesions in avulsed flaps by macroscopic measurement of necrosis and histological ulcer scoring using the National Pressure Ulcer Advisory Panel (NPUAP) Scale. Results: The average length of necrosis in avulsed tail flaps was 28.42 +/- 3.04 mm, whereas there was no necrosis in avulsed hindlimb flaps (p < 0.05). The average ulcer score of the lesions in tail and left hindlimb were 3.42 +/- 0.78, and 1.28 +/- 0.48, respectively (p < 0.05). Despite the lack of visible necrosis TUNEL staining revealed an increased amount of apoptotic cells in avulsed hindlimb flaps. Literature review revealed a significant variability in previous studies in terms of the amount of necrosis observed in tail degloving injury model. Conclusion: Tail degloving injury model proved to be a more reliable animal model for degloving injuries. However, standardization of the magnitude of degloving force is required to decrease the variability of necrosis observed in the literature. (C) 2017 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V.
Comparison of the inhibitory effect of different doses of subconjunctival bevacizumab application in an experimental model of corneal neovascularization
(2018) Ulas, Burak; Altan-Yaycioglu, Rana; Bal, Nebil; 30046522; AAG-3306-2019; AAL-4440-2020
AIM: To evaluate the inhibitory effect of subconjunctival bevacizumab as single- and multiple-dose application, and compare their effects on corneal neovascularization in a rat model. METHODS: Thirty adult Sprague-Dawley rats were used in this experimental study. The central cornea of the rats was cauterized chemically. The rats were randomly enrolled into three groups. All groups received subconjunctival injections. In Group 1 (control group, n=10), 0.05 mL 0.9% NaCl solution was injected on the first day. In Group 2 (single-dose group, n=10), 0.05 mL bevacizumab (1.25 mg) was injected on the first day. In Group 3 (multiple-dose group, n=10), four doses of 0.05 mL bevacizumab (1.25 mg) were injected on the first, third, fifth and seventh day. Slit-lamp examination of all rats was performed at the third and ninth day. Digital images of the corneas were taken and analyzed using image analysis software to calculate corneal neovascularization area. All rats were sacrificed on the tenth day. In corneal sections, the number of blood vessels, state of inflammation and collagen formation was evaluated histopathologically. RESULTS: In Group 3, corneal edema grades were significantly lower than Group 1 and Group 2 (P=0.02, and P=0.035, respectively). The mean percentage of neovascularized corneal area in Group 3 was significantly lower than Group 2 (P=0.005). On histopathological examination, Group 2 and Group 3 showed significantly less number of blood vessels than Group 1 (P=0.005, and P=0.001, respectively). Additionally, Group 3 showed significantly less number of blood vessels compared to Group 2 (P=0.019). Inflammation and edema grades were significantly lower in Group 3 compared to Group 1 (P=0.001). CONCLUSION: Subconjunctival bevacizumab injection is effective in inhibition of newly formed corneal neovascularization. The multiple-dose bevacizumab treatment seems to be more effective compared to single-dose treatment.
Rat modelinde topikal rifamisin uygulamasının ototoksik ve orta kulak mukozası üzerine etkilerinin araştırılması deneysel çalışma
(Başkent Üniversitesi Tıp Fakültesi, 2016) Yılmaz, Serkan; Yılmaz, İsmail
Amaç: Ama kronik otit modelinde topikal rifami inin (1) rat orta kulak mukoza ı üzerine ola ı hi topatolojik etkilerini araştırmak; (2) işitme üzerine ola ı olum uz etkilerini fonk iyonel yoldan araştırmaktır. Bu alışma ile kulağa damla yoluyla uygulanan rifami inin güvenilir olup olmadığı hakkında literatüre katkıda bulunmak hedeflenmiştir. Gereç ve Yöntem: Bu deney el alışma Başkent Üniver ite i ıp Fakülte i Deney Hayvanları Araştırma Laboratuvarında 30 adet rat üzerinde yapıldı. Ratlar tedavi ürelerine göre 3 guruba ayrıldı. Her iki timpanik membran perfore edildikten sonra ağ kulaklara rifami in günde 3x2 damla olarak uygulandı. Sol kulaklara i e herhangi bir tedavi verilmedi. Grup I’e 1 hafta, grup II’ye 2 hafta, grup III’e 3 hafta tedavi verildi. edavi önce i ve onra ında her iki kulağın di tor iyon ürünü otoaku tik emi yon (DPOAE) öl ümleri, sinyal gürültü oranı (SNR) öl üt alınarak yapıldı. edavi bitiminde ratlar dekapite edilerek orta kulak mukozaları di eke edildi ve patolojiye kör olarak te lim edildi. Bulgular: Tedavi verilen kulaklarda grup I’de 2 kHz’de perfora yon onra ına göre SNR’de anlamlı artış (p=0.022); kontrol kulaklarda grup I de 6 kHz’de anlamlı artış gözlendi (p=0.022). Perforasyon sonra ı ve tedavi onra ı SNR değerleri ağ ve ol kulaklar ara ında karşılaştırıldığında tüm frekan larda i tati tik el olarak anlamlı farklılık gözlenmedi (p >0.05). SNR değerleri gruplar ara ında karşılaştırıldığında tüm frekan larda tedavi önce i ve sonra ında anlamlı farklılık aptanmadı (p >0.017; Bonferroni düzeltmeli). Histopatolojik olarak rifami in verilen ağ kulaklar ile kontrol ol kulaklar ara ında inflama yon, fibrozi , yabancı ci im reak iyonu, va küler prolifera yon ve pigment i eren hi tio it a ı ından anlamlı farklılık aptanmadı (p>0,05). Ancak ağ kulakta gruplar ara ında pigment i eren hi tio itler grup I ve II’de anlamlı olarak yük ek bulundu (p=0.018). onuçlar: I) Bu alışma topikal rifami in uygulama ının ratlarda orta kulak mukoza ı üzerine inflama yon, fibrozi , yabancı ci im reak iyonu, va küler prolifera yon ve pigment i eren hi tio itler a ı ından kontrol kulaklar ile karşılaştırıldığında anlamlı bir etki inin olmadığını ortaya koymuştur. edavi verilen kulaklarda ilk iki hafta pigment i eren hi tio it ayı ında artış olduğu, ancak bu durumun ü üncü hafta düzeldiği gözlenmiştir. II) Topikal rifami in uygulama ının ratlarda, hi bir SNR değerinde anlamlı azalmaya neden olmadığı i in, ratlarda 2-6 kHz ara ı işitme üzerine ototok ik etki inin olmadığı onucuna varılmıştır. III) Bu bulgulara göre kronik otit modelinde topikal rifami in uygulama ının 3 hafta kullanımda bile hem orta kulak mukoza ı hem de ototok i ite yönünden güvenli olduğu onucuna varılmıştır. IV) Bu onu ların i kulak hi topatoloji inin ve yük ek frekan işitme eşiklerinin değerlendirildiği ileri deney el ve klinik alışmalar ile de teklenme i gerektiği düşünülmüştür. Purpose: The aim of this study is to investigate the use of topical rifamycin in chronic otitis media model about (1) the possible histopathological effects on the rat middle ear mucosa (2) the potential negative effects on hearing in functional way. It is targeted with this study to contribute literature about whether rifampicin applied as ear drops is reliable. Materials and Methods: This experimental study was conducted on 30 rats, in Baskent University Faculty of Medicine Experimental Animal Research Laboratory. The rats were divided into 3 groups according to the duration of treatment. After perforation of the both tympanic membrane rifamycin 3x2 drops per day was applied to the right ear. While the left ear did not receive any treatment. Group I 1 week, group II 2 weeks, group III 3 weeks of treatment were given. Before and after treatment in both ears, the distortion product otoacoustic emissions (DPOAE) measurements, is performed considering signal to noise ratio (SNR). After the treatment rats were decapitated and middle ear mucosa was dissected and was delivered blind to the pathology. Results: In the treated ears in group I at 2 kHz significant increase in SNR (p = 0.022) was observed relative to upon perforation of the ear; In the control ear in group I showed a significant increase in 6 kHz. After perforation and post-treatment SNR values compared to between right and left ears at all frequencies statistically no significant difference was observed (p> 0.05). SNR values compared between groups all frequencies before and after treatment showed no significant difference (p >0.017; Bonferroni correction). Histopathologically between rifampicin administered right ears and control left ears no significant differences were found in terms of; inflammation, fibrosis, foreign body reaction, vascular proliferation and pigment containing histiocytes (p> 0.05). However, in the right ear between groups, pigment containing histiocytes were significantly higher in the group I and II (p = 0.018). Conclusions: I) This study showed that topical rifampicin application in rats have no significant effect on middle ear mucosa in terms of inflammation, fibrosis, foreign body reactions, vascular proliferation and pigment containing histiocytes, compared to control ears. In treatment given ear increase in the number of histiocytes containing pigments in the first two weeks has been observed, but in the third week this situation improves. II) Whereas topical application of rifamycin in rats, caused no is significantly lower SNR value, it was concluded that between 2-6 kHz no ototoxic effects on hearing exists. III) based on these findings, it was concluded to be in chronic otitis model application of topical rifamycin even for 3 weeks is safe for the ototoxicity and middle ear mucosa. IV) It is thought that these results should be supported by forward experimental and clinical studies evaluating the inner ear histopathology and high frequency hearing thresholds.

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