Critical role of SDF-1/CXCR4 signaling pathway in stem cell homing in the deafened rat cochlea after acoustic trauma.

Previous animal studies have shown that stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor-4 (CXCR4) signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal stem cells (BMSCs) to the injured area. In the present study, we aimed to investigate the potential role of chemotactic SDF-1/CXCR4 signaling pathway in the homing of transplanted BMSCs to the injured cochlea after noise-induced hearing loss (NIHL) in a rat model. White noise exposure (110 dB) paradigm was used for hearing loss induction in male rats for 6 hours in 5 days. Distortion-product otoacoustic emission (DPOAE) responses were recorded before the experiment and post noise exposure. Hoechst 33342-labeled BMSCs and CXCR4 antagonist (AMD3100)-treated BMSCs were injected into the rat cochlea through the round window. SDF-1 protein expression in the cochlear tissue was assayed using western blot assay. The number of labeled BMSCs reaching the endolymph was determined after 24 hours. SDF-1 was significantly increased in the cochlear tissue of rats in the noise exposure group than in the control group. The number of Hoechst 33342-labeled BMSCs reaching the endolymph of the cochlea was significantly smaller in the AMD3100-treated BMSCs group than in the normal BMSCs group. Our present findings suggest that the SDF-1/CXCR4 signaling pathway has a critical role in BMSCs migration to the injured cochlea in a rat model of noise-induced hearing loss.

A brief report of plexiform neurofibroma.

Plexiform neurofibroma (PNF) is a rare variant of neurofibromatosis type1 (NF-1), which histopathologically, is a subtype of benign nerve sheath tumors, neurofibromas (NF). It develops as a result of proliferation in all parts of peripheral nervous system and can cause the functional damage, deformities, pain, considerable mortality, and morbidity and even the increasing risk of malignant transformation in some critical cases. Currently, the surgical intervention is the treatment of choice for PNF patients, which due to the tumor invasion, massive growth, and the chance of postoperative regrowth is not possible. The diagnosis of isolated tumor is an uncommon event. Considering the rarity of this neoplasm, herein, we describe a case of isolated PNF, so the purpose of this presenting is the rarity of recording. We describe a case of isolated plexiform neurofibroma presented with 7-year history of a slowly growing postauricular soft subcutaneous mass in a 14-year-old boy, which caused the right auricular deformity. After initial evaluation by imaging studies, the patient underwent to surgical resection of the mass and the diagnosis of plexiform neurofibroma was confirmed by histopathologic examination. Surgical excision of the mass had been done before which concluded the satisfactory result and based on oncologist diagnosis, further intervention such as radiotherapy or chemotherapy was not needed. The patient left the hospital with a clinical stability and was suggested to continue the regular follow-up. In conclusion, considering neurofibroma (NF) as differential diagnosis for subcutaneous masses in head and neck area is critical for early diagnosis and treatment procedure.