Objective: Brain-derived neurotrophic factor (BDNF) promotes the development and differentiation of neurons and synapses, as well as neuronal survival, by acting on specific neuronal groups in the central and peripheral nervous systems. However, the direct effect of BDNF on apoptosis in peripheral tissues is not known. The aim of this study was to investigate the relationship between BDNF and apoptosis, and the density and distribution of BDNF receptors in liver and kidney tissues by histological and immunehistochemical methods.Methods: Seven wild-type and 7 BDNF heterozygous (reduced BDNF levels) male mice were used in the study. Caspase-3 and TUNEL immunehistochemical stainings were performed in order to investigate the presence of apoptosis in the liver and kidney tissues of the studied groups. Apoptosis-entering cells were counted and the groups were compared. Concentration and distribution of BDNF receptors, tropomyosin-related kinase B (TrkB) and nerve growth factor receptor p75 (NGFR p75), in liver and kidney tissues were also examined by immunehistochemical analyzes.Results: As a result of Caspase-3 and TUNEL immunehistochemical staining, more cells were counted to enter the apoptotic process in sections of BDNF heterozygous group compared to control group (p<0.0001). In both groups TrkB and NGFR p75 receptors in liver and kidney tissues were determined in trace amounts, but there was no difference in intensity and distribution between the studied groups.Conclusion: According to our histological and immunehistochemical stainings and statistical analysis of cell count between groups, it was found that BDNF is protective against apoptosis in liver and kidney. The lack of difference between the studied groups in terms of intensity and distribution of BDNF receptors, suggests that BDNF receptor distribution in the liver and kidney tissues may be different from the nervous system or that BDNF may differ in affinity for these receptors. Keywords 316 Azaltılmış Beyin Kaynaklı Nörotrofik Faktörün (BDNF), Fare Karaciğer ve Böbrek Dokusuna Apoptotik EtkileriÖzet Amaç: Beyin kökenli nörotrofik faktör (BDNF), merkezi ve periferik sinir sisteminde belirli nöron grupları üzerine etki ederek, nöron ve sinapsların gelişimini ve farklılaşmasını, bunun yanında nöronal sağkalımı desteklemektedir. Periferik dokularda ise BDNF'nin apoptoz ile direkt ilişkisi bilinmemektedir. Bu çalışmada, karaciğer ve böbrek dokularında BDNF'nin apoptoz ile ilişkisi ve bu dokulardaki BDNF reseptörlerinin yoğunluk ve dağılımının histolojik ve immünohistokimyasal yöntemler kullanılarak araştırılması amaçlanmıştır.Yöntemler: Araştırmada 7 adet yabanıl tip ve 7 adet BDNF heterozigot (BDNF düzeyleri yarı yarıya azaltılmış) erkek fare kullanılmıştır. Karaciğer ve böbrek dokusunda apoptozun varlığını araştırmak amacıyla Kaspaz-3 ve TUNEL immünohistokimyasal boyamaları gerçekleştirilmiş ve apoptoza giren hücreler sayılarak gruplar arası karşılaştırma yapılmıştır. BDNF reseptörleri olan tropomiyozin-ilişkili kinaz B (TrkB) ve nerve growth fa...