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    Blind mole rat (Spalax leucodon) masseter muscle: structure, homology, diversification and nomenclature
    (VIA MEDICA, 2019) Yoldaş, Atilla; Demir, Mehmet Tevfik; İlgün, Ramazan; Dayan, Mustafa Orhun
    Background: It is well known that rodents are defined by a unique masticatory apparatus. The present study describes the design and structure of the masseter muscle of the blind mole rat (Spalax leucodon). The blind mole rat, which emerged 5.3-3.4 million years ago during the Late Pliocene period, is a subterranean, hypoxia-tolerant and cancer-resistant rodent. Yet, despite these impressive characteristics, no information exists on their masticatory musculature. Materials and methods: Fifteen adult blind mole rats were used in this study. Dissections were performed to investigate the anatomical characteristics of the masseter muscle. Results: The muscle was comprised of three different parts: the superficial masseter, the deep masseter and the zygomaticomandibularis muscle. The superficial masseter originated from the facial fossa at the ventral side of the infraorbital foramen. The deep masseter was separated into anterior and posterior parts. The anterior part of the zygomaticomandibularis muscle arose from the snout and passed through the infraorbital foramen to connect on the mandible. Conclusions: The construction of the deep masseter and zygomaticomandibularis muscles were of the Myomorpha type. Further studies are needed to reveal features such as muscle biomechanics, muscle types.
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    Effects of Testosterone Undecanoate Treatment on Some Oxidative Stress and Histopathological Parameters in Testicular Tissue of Rabbits
    (Universidade Federal do Rio Grande do Sul, 2025) Suvarıklı Alan, Beyza; Akçakavak, Gökhan; Camgöz, Avni; Tuzcu, Mehmet; Haliloğlu, Seyfullah; Dayan, Mustafa Orhun
    Studies on Anabolic androgenic steroids (AASs), which are increasingly used by many people, such as professional athletes, bodybuilders, in an uncontrolled manner with each passing day, have indicated that they can cause oxidative stress besides many side effects. The aim of the present study is to investigate the effects of testosterone undecanoate (TU), an anabolic steroid, on histopathological and oxidative stress in testicular tissues of New Zealand rabbits. Materials, Methods & Results: The study was conducted on 18 male New Zealand rabbits aged 5-6 weeks. The study involved three groups: the control group, the castor oil group, and the TU group, each of which included six New Zealand rabbits. While no treatment was provided to the control group, 0.2 mL castor oil was injected intramuscularly (IM) into the castor oil group and 0.2 mL TU (10 mg/kg) dissolved in castor oil was injected IM into the TU group for 6 weeks, 5 days a week. At the end of the experiment, testicular tissue samples of the animals that were euthanized under appropriate conditions were collected, and histopathological examinations and oxidative stress parameters in testicular tissue were analyzed. In the study, superoxide dismutases (SOD), glutathione (GSH), glutathione peroxidase (GPx) and catalase levels of testicular tissue in the TU injected group showed a statistically significant decrease compared to the control group (P < 0.05). When the macroscopic appearance of the testes was examined, it was found that the testes in the control and castor oil groups were macroscopically similar to each other, while the testes of the rabbits in the TU group appeared atrophic. When the mean Johnsen scores calculated in all groups were evaluated, it was observed that the control and castor oil groups were normal, while the TU group was thought to have maturation arrest. As a result of the histopathological examinations, the testicular tissue sections of the control group showed that the seminiferous tubules were regular and normal in diameter and size. When the testicular tissue sections of the castor oil group were examined, seminiferous tubules were found to be in good condition. The microscopic examination of the testicular tissues of the TU group showed atrophic changes in most of the seminiferous tubules. Besides the shrinkage in the size of these atrophic tubules, it was remarkable that the normal structure was disrupted and the cells were separated from the basal membrane and exfoliated into the lumen. Consequently, based on the findings that TU triggered oxidative stress in the testicular tissue of New Zealand rabbits and showed macroscopically and histopathologically adverse effects, it was concluded that the use of such AASs may cause significant health problems, and their use should be controlled. Discussion: Increased production of free radicals and weakening of the antioxidant defense system can lead to oxidative stress, which results in arterial blockages, severe damage to cells, and consequently impaired spermatogenesis. If the testicular biological system fails to detoxify or repair the negative effects of free radicals, cells and tissues are severely damaged. Long-term nandrolone decanoate (a testosterone preparation) treatment has been reported to decrease kidney tissue GSH and testicular tissue SOD levels in rats and New Zealand rabbits. Similarly, injection of boldenone undecylenate, an AAS, was noted to significantly reduce SOD, GSH, and catalase levels in the testicular tissue of rats, an indicator of oxidative stress in rat testes. The present study showed a statistically significant decrease (P < 0.05) in testicular tissue SOD, GSH, GPx, and catalase levels in the group to which TU was injected and this finding was consistent with the findings of previous studies.