Diabetes mellitus führt zur Akkumulation von dendritischen Zellen und zur Zerstörung des subbasalen Nervenplexus der Cornea in der Maus

Diabetes mellitus leads to accumulation of dendritic cells and nerve fiber damage of the subbasal nerve plexus in the murine cornea The current study was conducted to evaluate a possible relationship between a loss of nerve fibers of the SNP and the recruitment or infiltration of DCs in the diabetic cornea. It includes the analysis of the cornea over a period of nine weeks by the use of two different animal models presenting DM I and DM II. The results measured by quantification of the DCD, NFD, NFT and Co-Localization of DCs and nerve fibers of the SNP are mainly based on the in vivo CCM. To investigate the cellular structures in a qualitative manner, we used specific cell surface markers and analyzed the prepared corneal whole mounts with confocal microscopy. The results and the subsequent discussion led to the following conclusion: (1) Regression analysis showed a significant positive correlation of the increased BG-level and the increased DCD in STZ-treated BALB/c mice. In ob/ob mice there was a significant negative correlation between both parameters. (2) The DCD of STZ-treated BALB/c mice showed a gradual increase over the period of one to nine weeks in contrast to the ob/ob mice with a nearly constant high level of DCD. (3) Regression analysis of DCD and NFD showed a significant negative correlation in of STZ-treated BALB/c mice. This observation could not be confirmed in ob/ob mice. (4) The NFT in STZ-treated BALB/c and ob/ob mice showed a relative constant level over the whole period of nine weeks. (5) The Co-Localization of DCs and nerve fibers of the SNP did not show any differences over the whole period of nine weeks. The current study was able to show a relation between the loss of corneal nerve fibers and the increase of DCs under diabetic conditions. We suppose that a high BG-level and the related metabolic changes lead to a recruitment of DCs into the cornea and consequently to inflammation. Due to an interaction between nerve fibers and DCs soluble factors like cytokines or the formation of MNTs could lead to corneal polyneuropathy. To verify this assumption, cellular and molecular mechanisms between nerve fibers and DCs have to be analyzed to provide information on a functional association of both cell types in the diabetic cornea.