Abstract
Purpose :
Patients with diabetes mellitus (DM) may develop corneal complications and delayed wound healing. The aims of this study are to delineate the unique involvement of TGFβ3 in mediating epithelial wound healing in diabetic corneas.
Methods :
C57BL/6 mice were induced to develop diabetes by streptozotocin. TGFβ1, TGFβ3 or BSA as the control were subconjunctivally injected to the DM corneas 4 hours before epithelial debridement. The effects of TGFβ1 versus TGFβ3 on corneal epithelial wound closure, sensory nerve regeneration (whole mount confocal microscopy with β-tubllin III), and fibrosis (α-Smooth muscle actin, collagen I and III staining of cryostat sections) were compared in the DM corneas treated TGFβ1 or TGFβ3. To understand molecular mechanisms underlying high efficacy of TGFβ3, CECs, collected at 0 and 24 h post wounding, were used for a genome-wide microarray to compare the gene expression profiles. Differential expression of selected genes in TGFβ1 and β3 treated DM mouse corneas was confirmed by real-time PCR.
Results :
Both exogenous TGFβ1 and 3 accelerated delayed epithelial wound closure; however, TGFβ3 was significantly more effective comparing to TGFβ1 in DM B6 mouse corneas. At 3dpw, TGFβ1 treatment resulted in the formation of a sensory nerve fiber network with a higher density of nerve endings compare with DM, untreated corneas; the network, however, did not extend as far as that in TGFβ3 treated DM corneas. Presence of TGFβ1 resulted in a marked increase the α-SMa positive cells compare to TGFβ3 treated corneas, particularly near the leading edge. Genome-wide microarray revealed 394 (214 increase and 180 decrease) probe sets differentially expressed in TGFβ3 versus TGFβ1 treaded healing DM corneal epithelia. Real-time PCR and/or immunohistochemistry data confirmed the differential expression of several genes, such as TBL3 and CCL3.
Conclusions :
For the first time, TGFβ3 was shown to play a unique role, comparing with TGFβ1 in mediating epithelial wound healing. The impaired expression of TGFβ3 may contribute to delayed wound healing in DM corneas; hence, recombinant TGFβ3 may be used for treating diabetic neuropathy and keratopathy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.