Desiccating environmental stress exacerbates autoimmune lacrimal keratoconjunctivitis in non-obese diabetic mice

The non-obese diabetic (NOD) mouse is prone to develop autoimmune disease, including Sjögren's syndrome. The purpose of this study was to determine if desiccating environmental stress exacerbates the development of Sjögren's syndrome-like lacrimal keratoconjunctivitis in the NOD.B10.H2^b mouse. Four-week-old male mice were used as young controls. Sixteen-week-old male mice were untreated or subjected to desiccating stress with a fan alone or with a fan plus subcutaneous injections of the anticholinergic agent scopolamine for 5 or 10 days to inhibit tear production. Mice spontaneously developed Sjögren's syndrome-like lacrimal keratoconjunctivitis as they aged. Desiccating stress increased CD4+ and CCR5+ cells and decreased CD8+ cells in the conjunctival epithelium and lacrimal gland. Intraepithelial γδ T cells significantly decreased after 5 days and returned to baseline levels after 10 days in both groups exposed to desiccating stress. These immunopathological changes were accompanied by a decrease in conjunctival goblet cell density. Greater matrix metalloproteinase-9 production, gelatinase activity and loss of epithelial cell membrane CD25 immunoreactivity was noted in the ocular surface epithelia of stressed mice. These findings indicate that desiccating environmental stress aggravates Sjögren's syndrome-like lacrimal keratoconjunctivitis in the NOD mouse which has defective immunoregulation.