Abstract

Boron is a non-metal element, commonly found in Nature as borates in sedimentary rocks, charcoal, oceans and soils. In Chile, it is found in high concentrations in the drinkable water of the XV region, in Arica city, in concentrations that exceed the WHO normative. The present work evaluates the effect of boron at a dose of 12 mg/L of water (equivalent to 0.0686 g of boric acid) given orally for 8,42 and 49 days to 3 experimental groups of 10 mice each. Liver sections were stained with PAS-hematoxyline (to evaluate glycogen), Mallory (to identify collagen fibers) and Picrosirius red with polarizing light to classify collagen fibers. Results indicate that boron evokes diverse effects in liver. Binucleated cells were evaluated and counted and results were analyzed with the non-parametric Mann-Whitney test. Control group (8-day-old mice) had 22.9 binucleated cells per 200 hepatocytes and the boron exposed group (8-day-old mice) showed 28.5 (p>0.05). Therefore, there are not significant differences among these groups. In the 126-day-old mice, the control group had 43.9 binucleated cells per 200 hepatocytes and the boron exposed group showed 76.0, a statistically significant difference (p<0.01). Regarding PAS staining, intensity was classified as low, moderate or intense and analysis was done with the Chi-Square test. All control and experimental groups differed with slight statistical significance (p=0.05). With regard to Mallory staining, intensity was examined in two specific areas: portal triads (PTr) and central veins (CV). There were significant augments in both PTr and CV results after experimental and control groups comparison. Picrosirius red staining examined in polarized microscopy revealed that collagen III was predominant in boron treated mice, denoting collagenolysis of collagen I as toxical effect of boron. In conclusion, boron alters glycogen distribution and collagen quality and deposition in the two examined areas, whereas binucleated cells behave differently in young and adult animals.