This paper aims to explore the effect of MnCl2 on the mitochondrial function of human lung cells, and to study the changes of protein expression level of nuclear respiratory factor-1 (NRF-1)in mitochondrial dysfunction induced by MnCl2. The effects of MnCl2 on cell survival rate were assessed by the reductions of tetrazolium dye (MTT) in cultured cell lines 16HBE and A549 cells. All tested 16HBE and A549 cells were incubated with different concentrations of MnCl2. The permeability transition pore (PTP) of mitochondria, mitochondrial membrane potential and the inhibition rate of mitochondrial enzymes as indicators of mitochondrial damage were measured by fluorescent spectrometry and MTT assay, respectively. Apoptosis was detected by flow cytometry. Protein levels of NRF-1 and mtTFA were measured by Western blot assay. MnCl2 decreased the survival rate of the two cell lines. The IC50 of 16HBE and A549 cells were 1.91 mmol/L and 1.98 mmol/L, respectively. MnCl2 caused a concentration-dependent decrease of mitochondrial enzymes and the inhibition rates of mitochondrial enzymes of the two cell lines induced by 1.00 mmol/L MnCl2 were (52.8(5.4)% and (50.6(2.2)%, respiratory. The PTP opening increased in MnCl2-treated cells in a dose- and time-dependent manner. Compared with that in the control group, mitochondrial membrane potential in the two cell lines was decreased by MnCl2, by (7.9(3.0)%, (26.2(2.2)% and (27.8(4.1)% in the 16HBE cells, and (4.7(1.0)%, (14.9 (2.4)% and (27.5(1.2)% in the A549 cells. Increased apoptosis rates of the two cell lines were induced by 1.00 mmol/L MnCl2, (12.3(1.9) % and (6.0(0.4) %, respiratory. The results of Western blot assay revealed that the protein levels of NRF-1 and mtTFA were decreased in manganese-treated cells in a dose-dependent manner, with a significant difference compared with that of the control cells (P<0.05). MnCl2 induces mitochondrial dysfunction in 16HBE and A549 cells, and decreases the expression level of nuclear respiratory factor-1 (NRF-1), indicating that NRF-1 may play an important role in mitochondrial dysfunction.
Authors: Bao, Yan; Li, Jue; Zhang, Lijuan ;Full Source: Zhonghua Zhongliu Zazhi 2011, 33(3), 169-173 (Ch) ;