Exploration On The Combined Role And The Mechanism Of Fluorine And Aluminum On Hippocampus Neural Cell Apoptosis In Rats Induced By Tea-type Fluorosis

Objective:To investigate the combined role of fluorine and aluminum on hippocampus neural cell apoptosis in rats induced by drinking black tea fluorosis.Metholds:4-week male Sprague Dawley rats were randomized into 5 group according to their body weight:control group,fluoride treated group(20.1mg/L F as NaF),aluminum treated group(61.9mg/L Al as AlCl₃), fluoride with aluminum treated group(20.1mg/L F and 61.9mg/L Al),and black-tea treated group(20.1mg/L F and 61.9mg/L Al).The experiment lasted for 6 months.Histological sections of hippocampus were stained with hematoxylin & eosin(H&E),Cresyl violet(Nissl stain).TUNEL was used to detect apoptosis of hippocampus neural cells.And the mRNA and protein expression of Bcl-2 and Bax in the hippocampus were determined by RT-PCR and immunohistochemistry techniques.Results:No differences were found between the water intake of rats in the different treatment groups.Compared with the control group,the hippocampus neural cell apoptosis index was higher in every experiment group(P＜0.01) and fluoride with aluminum treated group was the highest in all groups.Fluorine and aluminum have an interaction on the hippocampus neural cell apoptosis(F=6.38, P＜0.05).The combination of fluorine with aluminum had a synergistic effect on the relative mRNA levels of Bax(F=13.05,P＜0.01).Fluorine and aluminum, solely or simultaneity ingested,could upregulate the protein expression of BCL-2,BAX in hippocampus neural cells.The protein expressin of BCL-2 and BAX were significantly inscreased in black-tea treated group as compared to control grouo.When compared with fluoride with aluminum treated group,the protein expressin of BCL-2 and BAX were significantly descreased.Conclusions:To some degree,combination of fluorine with aluminum promotes the neural cell apoptosis in CA₃ sector of the hippocampus of rats.The prolonged oral ingestion of black-tea liquor containing a relative high of fluorine and aluminum,could lead to apoptosis,and some of the toxicity seemingly associated with F or Al may be due to the effect of an Al-F complex.