The enhanced elimination of tissue methylmercury in Parachlorella beijerinckii-fed mice

Abstract

Chlorella (Parachlorella beijerinckii) on the excretion and tissue accumulation of methylmercury (MeHg), we orally administered 5 mg/kg of MeHg chloride (4 mg Hg/kg) to female C57BL/6N mice (aged 10 weeks). The mice were housed in metabolism cages to collect urine and feces for 3 weeks with diets containing 0%, 5%, or 10% P. beijerinckii powder (BP) in -increases in the cumulative Hg eliminations into urine (5% BP) and feces (5% and 10% BP) were found in the BP groups. Twenty-one days after administration, the organ Hg levels in both BP groups tended to decrease compared to that of the control group. The reduction of Hg levels in the kidney and brain were to glutathione (GSH) metabolism, no difference was found in GSH levels in the blood or organs between the control group and the 10% BP group. These results suggest that continuous BP intake accelerates the excretion of MeHg and subsequently decreases tissue Hg levels in mice, with no alteration of GSH metabolism. We should conduct further research to elucidate details regarding the mechanism of BP-induced enhancement of MeHg excretion.

Chlorella suppresses methylmercury transfer to the fetus in pregnant mice

“…The neonate and mother blood levels in the CP diet group were lower by 13.6% and 15.0%, respectively, than the basal diet group. In the case of a single injection of MeHg to female mice of the same strain, CP-induced reduction of the blood Hg became significant for the first time as late as 7 days after injection (Uchikawa et al, 2011). The sustained MeHg exposure for several weeks in this study might be more suitable than a single injection to detect the effects of CP to reduce blood Hg levels.…”

“…We have recently reported that Hg excretions into feces and urine in MeHg-treated female mice increase with co-administration of CP (Uchikawa et al, 2010) or feeding a CP diet (Uchikawa et al, 2011). Although we did not collect urine and feces using a metabolism cage in the Tissue Hg level (μg/g) was divided by blood Hg levels (μg/ml) in each mouse, and the mean ± S.D.…”

“…We have recently reported that chlorella intake enhances the tissue elimination of MeHg through stimulation of the excretion (Uchikawa et al, 2010(Uchikawa et al, , 2011. In the present study, to examine the effects of chlorella on MeHg transfer from mother's blood to the fetus, we fed a test diet containing 10% chlorella powder (CP) to mice for 7 to 8 weeks, from 4 weeks before mating to parturition.…”

<i>Chlorella </i>supplementation decreases methylmercury concentrations of hair and blood in healthy volunteers

“…Previously, we found that Chlorella increased mercury excretion and lowered tissue mercury levels in MeHgtreated mice (Uchikawa et al, 2010(Uchikawa et al, , 2011. Fecal excretion constitutes a major route for the elimination of MeHg, about 90% of the total elimination, in most animal species including humans (Norseth and Clarkson, 1970;Miettinen et al, 1971;Komsta-Szumska et al, 1983;WHO, 1990).…”

“…Thus, the discovery of a food material that could help detoxify the body from MeHg would be considered to beneficial to human health. We previously reported that Chlorella promoted the excretion of MeHg in both feces and urine, such that long-term administration of Chlorella enhances the elimination of tissue methylmercury in mice (Uchikawa et al, 2010(Uchikawa et al, , 2011. Here we studied the effect of 3-month Chlorella supplementation on mercury concentrations of blood and hair in healthy subjects.…”