Abstract
Purpose:
To investigate the effects of loss of nitric oxide synthase type II (NOS2) in the healing of an injured corneal stroma in mice. Cell culture experiments were also conducted to clarify the effects of lacking NOS2 on ocular fibroblast gene expression.
Methods:
The effect of lacking NOS2 on corneal stroma wound healing following an incision injury was evaluated by using NOS2-null (KO) mice. Histological, immunohistochemical and mRNA expression analyses were performed. Ocular fibroblasts from wild type (WT) and KO mice were used to study the role of NOS2 on fibrogenic gene expression.
Results:
Healing of an incision injury in corneal stroma was delayed with less invasion of macrophages and reduction in expression of aSMA and fibronectin in a KO mouse as compared with a WT mouse. In vitro experiments showed that the loss of NOS2 suppressed mRNA expression of TGFb1 and collagen Ia1, but not MCP-1, in ocular fibroblasts. Being inconsistent with the in vivo finding, lacking NOS2 upregulated a-smooth muscle actin mRNA in simple ocular fibroblast culture.
Conclusions:
NOS2 is required for macrophage invasion and primary healing of injured corneal stroma folowing incision injury. Appearance of myofibroblasts in the injured corneal stroma was suppressed by lacking NOS2 in vivo, although the loss of NOS2 promoted myofibroblast generation in vitro in monolayer culture.
Keywords: 765 wound healing •
484 cornea: stroma and keratocytes