C57bl 6jrj

In total, we used 32 C57BL/6JRj (Mus musculus f. domesticus, 16 males, 16 females) and 8 male B6D2(C57BL/6JRj × DBA/2JRj)F1 hybrid mice which were purchased from Janvier Laboratories (Staint-Berthevin Cedex, France) at the age of 8 weeks. Sample sizes were estimated with power statistics based on similar studies assessing fecal corticosterone metabolites in mice [16 (link),29 (link)]. Upon arrival, animals from the same strain were housed in same sex groups in mouse open top cages (type IIL, 36.5 × 20.7 × 14 cm, Tecniplast, Buguggiate, Italy). Cages were equipped with wooden bedding (LIGNOCEL^® 3–4 S, J. Rettenmaier and Söhne GmbH + Co. KG, Rosenberg, Germany), nesting material (Pur-Zellin 4 × 5 cm; Paul Hartmann GmbH, Wiener Neudorf, Austria) and cardboard tubes (7.6 × 3.8 cm diameter, Special Diet Service, Claus GmbH, Limburgerhof, Germany). Commercial mouse diet (ssniff^®, V1534, Soest, Germany) and tab water were provided ad libitum. Ten days prior to the start of the experimental sample collections, mice were housed individually to control fluctuations in testosterone levels related to social interactions and to habituate mice to the single housing condition during the experiments. Standard laboratory conditions (temperature 21 ± 1 °C, humidity 40–55%, light-dark cycle: 12:12 h, lights on at 8:00 a.m.) were maintained in the colony and during the experiment.

C57BL/6JRj (Janvier Labs, Le Genest-Saint-Isle, France) female mice. The animals were kept in a controlled environment (12:12 h light:dark cycle, 23 °C, 55–60% humidity) with free access to water and food (ssniff-Spezialdiäten GmbH, Soest, Germany). All animals were acclimatized for one week prior to experiments.

Female mice C57BL/6JRj aged 7 weeks (Janvier Labs, France) were randomly allocated to the experimental groups (Table S3) (N = 6–9 mice/group for inflammation, N = 6 for genotoxicity, N = 3–5 for histology/darkfield, N = 264 mice in total). The mice were acclimatized for 1 week before the start of the experiment. The caging conditions were as previously described [64 (link)]. Briefly, all mice were housed in polypropylene cages with bedding (sawdust) and activity enrichment at controlled environmental conditions; temperature (21 ± 1 °C), humidity (50% ± 10%) and 12 h light/dark period. Mice had access to food (Altromin 1324) and tap water ad libitum. The animals were assigned to intratracheal instillation at 8 weeks of age. The average body weight on the day of instillation was 17 ± 1 g, 17 ± 1 g and 19 ± 1 g for the GaP NW, CB and MWCNT exposure groups respectively. All procedures complied with the EC Directive 86/609/EEC and Danish law regulating experiments with animals (The Danish Ministry of Justice, Animal Experiments Inspectorate, permission 2015-15-0201-00465).

C57BL/6J, CBA/J and C57BL/6JRj (Janvier laboratory) wild-type mice of either sex between the postnatal day (P)9 and 11 months were deeply anesthetized with CO₂ and sacrificed by decapitation or cervical dislocation for immediate dissection of the utricle. For a subset of experiments, a Cre-dependent tdTomato reporter strain (Ai14; #007908 Jackson Laboratory; (Madisen et al., 2010 (link)); was crossbred with a Neurog1^CreERT2 mouse line (#008529 Jackson Laboratory; (Koundakjian et al., 2007 (link)); to sparsely label random vestibular ganglion neurons. All experiments complied with national animal care guidelines and were approved by the University of Göttingen Board for Animal Welfare and the Animal Welfare Office of the State of Lower Saxony.

Lmna^H222P/H222P mice [12 (link)] were backcrossed eight times with the congenic strains C57BL/6JRj and 129S2/svPasCrl (Janvier Labs). The animals were fed chow and housed in a disease-free barrier facility at 12 h/12 h light/dark cycles. The French Ministry of Health has approved all animal experiments (approval number #00982.03). Accredited personnel dedicated to the Care and Use of Experimental Animals has conducted all animal experiments (accreditation number #75–679). The animal experiments were performed according to the guidelines from Directive 2010/63/EU of the European Parliament on the protection of animals used for scientific purposes.