Neurobehavioural effects of exposure to fluoride in the earliest stages of rat development

GUMILAR F.; BARTOS M.; BRAS C.; GALLEGOS C.E.; MINETTI A.; GIANNUZZI L.

Florencia

Congreso; 53rd Annual Meeting of the International Association of Forensic Toxicologists (TIAFT); 2015

IntroductionIt is known that exposure to highconcentrations of Fluoride (F) produces deleterious health effects in humanpopulation. However, in the last years it has been concluded that lowconcentrations of F may have adverse health effects as well. Transplacental passageof F and its incorporation into fetal tissues has been demonstrated. Therefore,the purpose of the present work was to study the effects of the exposure to lowlevels of F during pregnancy and lactation on the central nervous systemfunctionality.AimsThe purpose of the present study was to studyin young and adult rats, the effect of exposure to low concentrations of Fduring pregnancy and lactation, on sensory-motor reflexes and on the anxiety level.MethodsPregnant female rats were exposed to 5 and 10mg/L F in drinking water during pregnancy and lactation. Starting on postnatalday 3, each pup received a battery of developmental tests: Righting reflex,Cliff aversion and Negative geotaxis. Also, the ear and eye opening wereassessed. One test trial per day was given to the pups on each test. Thedependent variable analysed for each test consisted in the postnatal day untilthe following criteria were reached by each pup. In the 45- and 90-day-oldoffspring, anxiety was determined using an elevated plus maze. The plus mazeconsisted of two arms enclosed and located perpendicularly to two openarms. The test exploits a rodent?s natural conflict between avoidance andexploration of open and elevated areas. The rats were placed in the center ofthe maze and were allowed to explore the maze freely for 5 min. The followingparameters were calculated: i) percentage of time spent in the open arms, ii)percentage of entries in the open arms, and iii) total number of arm entries.Increased time spent and entries in the open arms are consistent with adecrease in anxiety behavior. ResultsA significant delay in the development of eyeopening was observed in all offspring whose mothers had been exposed to the twoF concentrations tested (p<0.001). A low index of anxiety in the youngfemales (p>0.01for 5mg/LF and p<0.05 for 10 mg/L F) and in all adultoffspring (p<0.001 for female and male) exposed to the two F concentrationstested was also detected. ConclusionsThe present study shows that exposure to low Fconcentrations during pregnancy and lactation produces dysfunction in thecentral nervous system mechanisms which regulate motor and sensitivedevelopment and anxiety.