Toxic cyanobacterial blooms in freshwater have been considered as threats to human health. Microcystins are a family of cyclic polypeptides produced by cyanobacteria and are toxic to plants and animals. Microcystin-LR (MC-LR) is the most toxic variant among the microcystin family and could cause oxidative stress in various organs, including the reproduction system. The aim of this study was to investigate the effect of MC-LR on apoptosis of Sertoli cells that play an essential role in the development and maturation of sperm cells. Sertoli cells were isolated from healthy immature rats and cultured with MC-LR. The viability of Sertoli cells was decreased after treatment with MC-LR at 10 μg/ml for 24 h (P < 0.05). Moreover, the MC-LR-treated cells exhibited condensed chromatin and fragmented nuclei, features of apoptosis, as judged by Hoechst 33258 staining. We also analyzed the mRNA and protein levels of three apoptosis-related genes, p53, bax and bcl-2, using reverse transcription-polymerase chain reaction and Western blot analyses, respectively. Both p53 and bax function as promoters of apoptosis, while bcl-2 is an apoptotic suppressor. The mRNA and protein expression levels of p53 and bax were increased in Sertoli cells treated with MC-LR at 10 μg/ml compared with the control group (P < 0.05), while the bcl-2 protein levels were decreased in cells treated with MC-LR at 10 μg/ml (P < 0.05). Moreover, caspase-3 activity that is involved in the induction of apoptosis was significantly increased in Sertoli cells treated with MC-LR. These results indicate that MC-LR induces apoptosis of Sertoli cells.

Heme oxygenase-1 (HO-1) plays important roles in anti-oxidant, anti-inflammatory and immunoregulative activities. The aim of this study was to observe if HO-1 transfection could inhibit the damage of osteoblasts induced by ethanol. HO-1 was transfected into osteoblasts via constructed plasmid. After exposure to ethanol for 24 h, cytoactivity and apoptosis of osteoblasts were measured by MTT assay and flow cytometry, respectively. Furthermore, the oxidative stress and inflammatory factors in osteoblasts were measured. Compared to positive control group, the cytoactivity of transfected osteoblasts was significantly increased, and the apoptosis rate was significantly decreased (P<0.05). At the same time, the levels of reactive oxygen species (ROS), methane dicarboxylic aldehyde (MDA), tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) were significantly decreased (P<0.05), and superoxide dismutase (SOD) level was increased (P<0.05) in the transfected osteoblasts as compared with positive controls. These results suggest that HO-1 plays a protective role in osteoblasts, and HO-1 transfection can effectively inhibit bone damage induced by ethanol.