RESUMO
Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. However, IFT25, a component of the IFT complex, is not required for the formation of cilia in somatic tissues. In mice, the gene is highly expressed in the testis, and its expression is upregulated during the final phase when sperm flagella are formed. To investigate the role of IFT25 in sperm flagella formation, the gene was specifically disrupted in male germ cells. All homozygous knockout mice survived to adulthood and did not show any gross abnormalities. However, all homozygous knockout males were completely infertile. Sperm numbers were reduced and these sperm were completely immotile. Multiple morphological abnormalities were observed in sperm, including round heads, short and bent tails, with some tails showing branched flagella and others with frequent abnormal thicknesses, as well as swollen tips of the tail. Transmission electron microscopy revealed that flagellar accessory structures, including the fibrous sheath and outer dense fibers, were disorganized, and most sperm had also lost the "9+2" microtubule structure. In the testis, IFT25 forms a complex with other IFT proteins. In Ift25 knockout testes, IFT27, an IFT25 binding partner, was missing, and IFT20 and IFT81 levels were also reduced. Our findings suggest that IFT25, although not necessary for the formation of cilia in somatic cells, is indispensable for sperm flagellum formation and male fertility in mice.
Assuntos
Cílios/fisiologia , Flagelos/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Espermatozoides/fisiologia , Animais , Fertilidade/genética , Flagelos/ultraestrutura , Infertilidade Masculina/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Knockout , Microtúbulos/ultraestrutura , Contagem de Espermatozoides , Motilidade dos Espermatozoides/genética , Espermatozoides/ultraestrutura , Testículo/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/fisiologiaRESUMO
Introduction: Intramuscular myxomas are rare, benign mesenchymal tumors which commonly arise in muscle of the upper limb, pelvis, abdominal tissue, spine, or facial muscle. There are few case reports of intramuscular myxomas, and none of these describe intramuscular myxoma as a cause of compressive neuropathy. Case Report: We describe the case of a 67-year-old woman who presented to us with a 1-year history of progressive enlargement of a painless right elbow mass. She gradually developed increasing numbness and tingling in her right small finger, which was worse at night. She underwent cubital tunnel release with concurrent right elbow mass excision of the flexor carpi ulnaris muscle. Histology showed intramuscular myxoma. Postoperatively, she had a complete resolution of her symptoms with a good functional outcome. Conclusion: This is the first known case of intramuscular myxoma within the flexor carpi ulnaris causing compressive neuropathy of the ulnar nerve at the elbow.