title: Impaired aquaporins expression in the gastrointestinal tract of rat after mercury exposure.
abstract: The main route of exposure to mercury in humans is through the diet. Consequently, the gastrointestinal mucosa is exposed to the mercurial forms, where they cause intestinal fluid accumulation, mucosal injuries and diarrhea. The relationship between inorganic mercury (HgCl2 ) and methylmercury (CH3 HgCl) exposure and water movement in the gastrointestinal tract is still unexplored. The leading role of aquaporins (AQPs) in the rapid bidirectional movement of fluid in the gastrointestinal tract of mammals is well established. The present study evaluates the effect of HgCl2 and CH3 HgCl exposure on AQP expression in different portions of the gastrointestinal tract of rats treated by gavage (5 mg kg(-1) of mercury species, single dose, 4 days). The results show that mercury species reduce mRNA and protein levels of AQPs in different parts of the gastrointestinal tract. In the stomach, treated rats show a significant reduction of expression of AQP3 (80-90% for mRNA and 50% for protein) and AQP4 (95-99% for mRNA and 20-40% for protein). In the small and large intestine, treated rats experience a significant reduction of AQP3 and AQP7 expression. Protein contents of both AQPs are reduced in similar proportions in jejunum (AQP3: 40-50%; AQP7: 45-50%) and colon (AQP3: 35-40%; AQP7: 45-60%), regardless of the treatment. Our results indicate that some AQPs are downregulated in the rat gastrointestinal tract by mercury exposure, suggesting a possible role of AQPs in the development of mercury gastrointestinal symptoms.
authors: Department of Molecular Medicine, Human Physiology Unit, University of Pavia, Pavia, Italy.
authors: Cinzia
authors: C
authors: Bottino
authors: Institute of Agrochemistry and Food Technology (IATA-CSIC), Paterna, Valencia, Spain.
authors: Marta
authors: M
authors: Vázquez
authors: Institute of Agrochemistry and Food Technology (IATA-CSIC), Paterna, Valencia, Spain.
authors: Vicenta
authors: V
authors: Devesa
authors: Department of Molecular Medicine, Human Physiology Unit, University of Pavia, Pavia, Italy.
authors: Umberto
authors: U
authors: Laforenza
mesh_terms: D000818:Animals; D020346:Aquaporins / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008627:Mercuric Chloride / Q000633:toxicity*; D008767:Methylmercury Compounds / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020346:Aquaporins; D008767:Methylmercury Compounds; D008627:Mercuric Chloride; C004925:methylmercuric chloride
keywords: aquaporins; colon; inorganic mercury; methylmercury; small intestine; stomach; water channels