title: Insulin replacement restores the vesicular secretory apparatus in the diabetic rat lacrimal gland.
abstract: OBJECTIVE
  In the lacrimal gland (LG) acinar cells, signaling regulates the release of secretory vesicles through specific Rab and SNARE exocytotic proteins. In diabetes mellitus (DM), the LGs are dysfunctional. The aim of this work was to determine if secretory apparatus changes were associated with any effects on the secretory vesicles (SV) in diabetic rats as well as the expression levels of constituent Rab and members of the SNARE family, and if insulin supplementation reversed those changes.
  
  
  METHODS
  DM was induced in male Wistar rats with an intravenous dose of streptozotocin (60 mg/kg). One of the two diabetic groups was then treated every other day with insulin (1 IU). A third control group was injected with vehicle. After 10 weeks, Western blotting and RT-PCR were used to compared the Rab and SNARE secretory factor levels in the LGs. Transmission electron microscopy evaluated acinar cell SV density and integrity.
  
  
  RESULTS
  In the diabetes mellitus group, there were fewer and enlarged SV. The Rab 27b, Rab 3d, and syntaxin-1 protein expression declined in the rats with diabetes mellitus. Insulin treatment restored the SV density and the Rab 27b and syntaxin expression to their control protein levels, whereas the Vamp 2 mRNA expression increased above the control levels.
  
  
  CONCLUSIONS
  Diabetes mellitus LG changes were associated with the declines in protein expression levels that were involved in supporting exocytosis and vesicular formation. They were partially reversed by insulin replacement therapy. These findings may help to improve therapeutic management of dry eye in diabetes mellitus.
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Dias
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Thiago Martins
authors.initials: TM
authors.lastname: Batista
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Letícia Prates
authors.initials: LP
authors.lastname: Roma
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Carolina Maria
authors.initials: CM
authors.lastname: Módulo
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Leonardo Tannus
authors.initials: LT
authors.lastname: Malki
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Lara Cristina
authors.initials: LC
authors.lastname: Dias
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Mônica
authors.initials: M
authors.lastname: Alves
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Peter Sol
authors.initials: PS
authors.lastname: Reinach
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Everardo Magalhães
authors.initials: EM
authors.lastname: Carneiro
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Eduardo Melani
authors.initials: EM
authors.lastname: Rocha
mesh_terms: D000109:Acetylcholine / Q000032:analysis; D061354:Acinar Cells / Q000648:ultrastructure; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000378:metabolism*; D005089:Exocytosis / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007765:Lacrimal Apparatus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D050765:Qa-SNARE Proteins / Q000378:metabolism; D050683:R-SNARE Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000187:drug effects / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D050765:Qa-SNARE Proteins; D050683:R-SNARE Proteins; D012333:RNA, Messenger; D020691:rab GTP-Binding Proteins; D000109:Acetylcholine