title: Microarray analysis of the rat lacrimal gland following the loss of parasympathetic control of secretion.
abstract: Previous studies showed that loss of muscarinic parasympathetic input to the lacrimal gland (LG) leads to a dramatic reduction in tear secretion and profound changes to LG structure. In this study, we used DNA microarrays to examine the regulation of the gene expression of the genes for secretory function and organization of the LG. Long-Evans rats anesthetized with a mixture of ketamine/xylazine (80:10 mg/kg) underwent unilateral sectioning of the greater superficial petrosal nerve, the input to the pterygopalatine ganglion. After 7 days, tear secretion was measured, the animals were killed, and structural changes in the LG were examined by light microscopy. Total RNA from control and experimental LGs (n = 5) was used for DNA microarray analysis employing the U34A GeneChip. Three statistical algorithms (detection, change call, and signal log ratio) were used to determine differential gene expression using the Microarray Suite (5.0) and Data Mining Tools (3.0). Tear secretion was significantly reduced and corneal ulcers developed in all experimental eyes. Light microscopy showed breakdown of the acinar structure of the LG. DNA microarray analysis showed downregulation of genes associated with the endoplasmic reticulum and Golgi, including genes involved in protein folding and processing. Conversely, transcripts for cytoskeleton and extracellular matrix components, inflammation, and apoptosis were upregulated. The number of significantly upregulated genes (116) was substantially greater than the number of downregulated genes (49). Removal of the main secretory input to the rat LG resulted in clinical symptoms associated with severe dry eye. Components of the secretory pathway were negatively affected, and the increase in cell proliferation and inflammation may lead to loss of organization in the parasympathectomized lacrimal gland.
authors.affiliation: LSU Eye Center, Lions Eye Research Laboratories, Laboratory for the Molecular Biology of the Ocular Surface, New Orleans, Louisiana 70112, USA.
authors.forename: Doan H
authors.initials: DH
authors.lastname: Nguyen
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Toshida
authors.forename: Jill
authors.initials: J
authors.lastname: Schurr
authors.forename: Roger W
authors.initials: RW
authors.lastname: Beuerman
mesh_terms: D000465:Algorithms; D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000502:physiology; D002455:Cell Division; D003320:Corneal Ulcer / Q000209:etiology; D015352:Dry Eye Syndromes / Q000209:etiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007249:Inflammation; D007765:Lacrimal Apparatus / Q000294:innervation / Q000378:metabolism*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D017764:Parasympathectomy; D010275:Parasympathetic Nervous System / Q000293:injuries / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020318:Rats, Long-Evans; D011976:Receptors, Muscarinic / Q000502:physiology; D013666:Tears / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D011976:Receptors, Muscarinic