title: Amelioration of chronic fluoride toxicity by calcium and fluoride-free water in rats.
abstract: The study was undertaken to explore the amelioration of chronic fluoride (F) toxicity (with low and normal Ca) in rats. The study was conducted in two phases. In phase I (6 months), seventy-six Wistar, weanling male rats were assigned to four treatment groups: normal-Ca (0·5 %) diet (NCD), Ca+F - ; low-Ca (0·25 %) diet (LCD), Ca - F - ; NCD +100 parts per million (ppm) F water, Ca+F+; LCD +100 ppm F water, Ca - F+. In phase II (reversal experiment, 3 months), LCD was replaced with the NCD. Treatment groups Ca+F+ and Ca - F+ were divided into two subgroups to compare the effect of continuation v. discontinuation along with Ca supplementation on reversal of chronic F toxicity. In phase I, significantly reduced food efficiency ratio (FER), body weight gain (BWG), faecal F excretion, serum Ca and increased bone F deposition were observed in the treatment group Ca - F+. Reduced serum 25-hydroxy-vitamin D3, increased 1,25-dihydroxy-vitamin D3 and up-regulation of Ca-sensing receptor, vitamin D receptor and S100 Ca-binding protein G (S100G) were observed in treatment groups Ca - F - and Ca - F+. In phase II (reversal phase), FER, BWG and serum Ca in treatment groups Ca - F+/Ca+F - and Ca - F+/Ca+F+ were still lower, as compared with other groups. However, other variables were comparable. Down-regulation of S100G was observed in F-fed groups (Ca+F+/Ca+F+ and Ca - F+/Ca+F+) in phase II. It is concluded that low Ca aggravates F toxicity, which can be ameliorated after providing adequate Ca and F-free water. However, chronic F toxicity can interfere with Ca absorption by down-regulating S100G expression irrespective of Ca nutrition.
authors.affiliation: National Institute of Nutrition, Food and Drug Toxicology Research Centre, Indian Council of Medical Research, Hyderabad 500 007, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Shankar
authors.forename: Sudip
authors.initials: S
authors.lastname: Ghosh
authors.forename: K
authors.initials: K
authors.lastname: Bhaskarachary
authors.forename: K
authors.initials: K
authors.lastname: Venkaiah
authors.forename: Arjun L
authors.initials: AL
authors.lastname: Khandare
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D064026:Calbindins; D002112:Calcifediol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000172:deficiency / Q000494:pharmacology / Q000627:therapeutic use*; D002136:Calcium, Dietary / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D002908:Chronic Disease; D004032:Diet; D019587:Dietary Supplements; D015536:Down-Regulation; D060766:Drinking Water / Q000737:chemistry*; D004734:Energy Metabolism / Q000187:drug effects; D005243:Feces / Q000737:chemistry; D005459:Fluorides / Q000378:metabolism / Q000633:toxicity*; D007408:Intestinal Absorption; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D044169:Receptors, Calcium-Sensing / Q000097:blood; D064030:S100 Calcium Binding Protein G / Q000097:blood; D015854:Up-Regulation; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D015430:Weight Gain / Q000187:drug effects
chemical_list: D064026:Calbindins; D002136:Calcium, Dietary; D060766:Drinking Water; D044169:Receptors, Calcium-Sensing; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D002112:Calcifediol; D005459:Fluorides; D002118:Calcium