Expression and significance of silence signal regulating factor 1 in cornea and trigeminal ganglion in type 1 diabetes model mice / 中华实验眼科杂志

ABSTRACT

Background Diabetes is one of the risk factors that leads to corneal neuropathy.Silent signal regulatory factor 1 (Sirt1) plays an important role in glucose metabolism,lipid metabolism,regulation of insulin secretion and is closely related to the nervous system disease.The relationship between Sirt1 and diabetic corneal neuropathy is not fully understood.Objective This study was to detect the expression of Sirtl in cornea and trigeminal ganglion with type 1 diabetes model mice and explore the association of Sirt1 expression with diabetic corneal neuropathy.Methods Eight C57BL/6-Ins2Akita/J male mice and eight wild-type C57BL/6 male mice in the same litter were selected as type 1 diabetes model group and control group,respectively.The mice of two groups were sacrificed in overdose anesthesia method at 12-month old.Histological examination of cornea and trigeminal ganglion was performed using hematoxylin and eosin staining.Expression and localization of Sift1 protein in cornea and trigeminal ganglion were detected using immunohistochemistry.Western blot assay and fluorescine quantitative PCR were respectively used to quantitatively analyze the expression of Sirt1 protein and Sirt1 mRNA.Results Trigeminal ganglion cells were uneven in size and shape with the loosened cellular arrangement and disorder neurofibrosis alignment,and the corneal epithelial cells were less in the C57BL/6-Ins2Akita/J mice,but the trigeminal ganglion cells and corneal epithelial cells were normal in wild-type C57BL/6 mice.Immunochemisty exhibited that Sirtl protein was expressed mainly in corneal epithelium and the expression of Sirtl protein was stronger in the C57BL/6 mice than that in C57BL/6-Ins2Akita/J mice.Fluorescine quantitative PCR assay showed that the gray scale value of Sirt1 mRNA in cornea in C57BL/6-Ins2Akita/J mice was lower than that of the wild-type C57BL/6 mice(0.56±0.03 vs.0.98±0.13) with significant difference (t =5.853,P =0.010).Western blot showed that the expression of Sirt1 protein in cornea was lower in C57BL/6-Ins2Akita/J mice than that of the wild-type C57BL/6 mice(0.78±0.017 vs.1.300±0.012) with significant difference(t =33.140,P =0.001).However,no significant differences were seen in the gray scale value of Sirt1 mRNA(2.45±0.18 vs.2.51±0.22) (t=0.587,P=0.599) and protein level(1.100±0.015 vs.1.110±0.017) (t =0.430,P=0.709) in trigeminal ganglion tissues between C57BL/6-Ins2Akita/J mice and wide-type C57BL/6 mice.Conclusions The corneal nerve and structure is abnormal in 12-month-old C57BL/6-Ins2Akita/J mouse.Sirt1 is involved in the pathogenesis of diabetic keratoneuropathy,suggesting that it may be a potential target.