Detection of fluid secretion of three-dimensional reconstructed eccrine sweat glands by magnetic resonance imaging

We previously showed three-dimensional (3D) reconstructed eccrine sweat glands have similar structures as native eccrine sweat glands, but whether the 3D reconstructed sweat glands appropriately secrete fluid is still unknown. In this study, Matrigel-embedded human eccrine sweat gland cells or Matrigel alone were implanted into the groin subcutis of the nude mice. Ten weeks post-implantation, images of the subcutaneously formed plugs, as well as footpads of rats, pre- and post-pilocarpine/normal saline (NS) injection were acquired using a fat-suppressed proton density-weighted magnetic resonance imaging (MRI) sequence at 7.0 T, and the regions of interest (ROIs) in plugs and rat footpads were analysed and graphed. A significant increase in the ROI mean proton intensity occurred in both 3D reconstructed and native eccrine sweat glands after pilocarpine injection. The mean proton intensity had no noticeable changes in ROIs of Matrigel plugs between pre- and post-pilocarpine injection, and in ROIs of rat footpads between pre- and post-NS injection. In conclusion, the 3D reconstructed sweat glands possess fluid secretion, which is detectable by fat-suppressed proton density-weighted MRI.