Abstract
Abstract: :
Purpose: To evaluate lacrimal gland gene expression response to corneal stimulation in the mouse. Methods: Following ARVO animal guidelines, groups of 4 anaesthetized BALB/c mice received bilateral silver nitrate burns, 5 seconds to cornea and 1 second to conjunctiva. Control mice were treated the same except they received no burns. After 3 and 24 hours, eight mouse lacrimal glands per group were harvested and the total RNA extracted from the pooled tissues by an acidic phenol/chloroform method. The Clontech Atlas cDNA Expression Array kits (mouse 1.2, cat # 7823-1, 1173 single spot genes/membrane) with nylon membranes were used to evaluate gene expression. The experiment was repeated three times. Differences in expression levels were determined by paired t-tests of the background-adjusted intensities of the 3 sets of control and burn samples. Results: For the 3-hour post burn group, 325 genes showed detectable expression of which 48 genes demonstrated consistent change in expression and almost all of these were down regulated. Down regulated genes included transcription activators and repressors, oncogenes & tumor suppressors, motor proteins, growth factors, cytokines & chemokines, and heat shock proteins. Up regulated genes included apoptosis associated, stress response proteins, serine proteases, and death receptors. For the 24-hour post burn group, 245 genes showed detectable expression of which 17 genes demonstrated consistent change in expression and most of these were up regulated. Up regulate genes included oncogenes & tumor suppressors, cyclins, and death kinases. Down regulated genes included serine proteases, apoptosis associated, and motor proteins. Mixed responses were seen in basic transcription and transcription activators and repressors. Conclusions: Gene expression in the lacrimal gland is altered at 3 and 24 hours post corneal trauma. Multiple systems appear to be affected. As this is preliminary work, we want to be cautious in the interpretation. The results might suggest that there was a decrease in cell proliferation and an increase in apoptosis at 3 hr and the opposite at 24hr. The 3 hr may be a reaction to trauma and the 24 hr may be the glands response or return to homeostasis. The 3 hr response is interesting because we did not stress the lacrimal cells directly. We might have anticipated more up regulation at 3 hr as part of an increase in lacrimal gland secretions. Ongoing experiments should improve our understanding of the short and long-term lacrimal gland stress response that occurs following cornea and conjunctiva stimulation.
Keywords: 452 lacrimal gland • 376 cornea: tears/tear film/dry eye • 370 cornea: basic science