{'fraction_non_alphanumeric': 0.04303599374021909, 'fraction_numerical': 0.023474178403755867, 'mean_word_length': 5.239024390243903, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effects of microcystin‐LR on patterns of iNOS and cytokine mRNA expression in macrophages in vitro

The presence of cyanobacterial toxins in drinking and recreational waters represent a potential health hazard to the public. Microcystin‐LR (MC‐LR) is the most commonly encountered toxin and is a potent cyclic heptapeptide hepatotoxin produced by cyanobacteria. In this study, the immunomodulation by MC‐LR of BALB/c mice peritoneal macrophages was investigated in vitro on mRNA levels of induced nitric oxide synthase and multiple cytokines by reverse‐transcription polymerase chain reaction (RT‐PCR). Lavaged peritoneal macrophages were incubated for 6 h with lipopolysaccharide (LPS) at a concentration of 100 μg/L and MC‐LR at doses of 1, 10, 100, and 1000 nmol/L. Total RNA was extracted from the incubated macrophages, and then the levels of mRNA for induced nitric oxide synthase (iNOS), IL‐1β, TNF‐α, GM‐CSF, and IFN‐γ were detected. The results showed that expression of mRNA for iNOS, IL‐1β, TNF‐α, GM‐CSF, and IFN‐γ decreased significantly compared to the positive control (LPS only). These results have led us to propose the need for the establishment of a survey of the immunotoxicity of microcystins. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 85–91, 2005.