The interstellar medium (ISM) plays a key role in understanding the star formation process. Moreover, the knowledge of the structure of the ISM of the high redshift galaxies, the ionizing sources of the early universe, can help to quantify the ionizing radiation escaping the ISM. While it is still difficult to assess the details of the ISM properties at high redshifts, the ‘chemically-young’ environment that characterizes the high-z galaxies can be found in the nearby low-metallicity dwarf galaxies. These galaxies show a prominent [OIII] 88 μm emission. This suggests a diffuse hard radiation field and a porous ISM, which facilitates the escape of ionizing photons. To investigate the structure of the ISM and quantify the escaping fraction of the ionizing photons in the low-metallicity galaxies, we investigated the electron density distribution of the nearby low-metallicity dwarf galaxies IC10. The distance of this galaxy (~750 kpc), makes IC10 a perfect target to investigate the electron density distribution at different special scales, from the HII regions scale to the entire galaxy scale. I will present the results of our study of the electron density distribution obtained by the combination of multi-infrared density diagnostics: ratios of mid- and far-infrared line emission observed by the Stratospheric Observatory for Infrared Astronomy (SOFIA), Herschel, and Spitzer.