Intravital Microscopy of the Rat Uterus After Titanium Dioxide Nanomaterial Exposure

Intravital microscopy has been used extensively to understand microvascular physiology while maintaining in situ neurogenic, humoral, and myogenic control. Endothelial cell and microvascular dysfunction after engineered nanomaterial exposure have been established using in vitro techniques. With the potential of engineered nanomaterials, contact can no longer be confined to occupational exposures of healthy males. Female diestrous SD rats were exposed to nano-TiO2 aerosols (176±6 nm, 10±0.5 mg/m3, 5 h; calculated pulmonary deposition of 41.6±2 µg). 24h post-exposure rats were anesthetized (Inactin, 100mg/kg, i.p.). The right horn of the uterus was exteriorized, gently secured over an optical pedestal at its in situ length, and enclosed in a warmed PSS tissue bath. Prior to functional measurements, leukocyte adhesion and rolling were assessed using a 20x water immersion objective to characterize significant elevation (157%) of leukocyte trafficking after TiO2 exposure. Microvascular reactivity was measured using ionophoretically applied acetylcholine (0.025M; ACh; 20, 40, 100, and 200 nA), sodium nitroprusside (0.05M; SNP; 20, 40, and 100 nA), or phenylephrine (0.05M; PE; 20, 40, and 100nA) to evaluate endothelium-dependent dilation (EDD), -independent dilation (EID), and vascular smooth muscle responsiveness (VSM), respectively. Passive diameter was established by superfusing the tissue with 10-4M adenosine. Overall, uterine dilation was significantly altered in response to ACh and SNP. Similar to males, female SD rats present systemic microvascular dysfunction; however due to uterine complexities, the reproductive ramifications after nanomaterial exposure must be determined. NIH-F32-ES023435(PAS); R01-ES015022(TRN)