An in vitro investigation of biochemical and molecular markers of nanomaterial toxicity to the intestine

Application of nanomaterials (NMs) cuts across all facets of life, including agriculture, food, medicine, cosmetics, textiles and electronics, and can lead to ingestion by humans. Although researchers have investigated the toxicity of NMs, there is still a paucity of studies which have assessed NM toxicity to the gastrointestinal (GI) tract. The Caco-2 cell line is most commonly used to assess impacts of NMs on the GI tract, but in vitro coculture models that are more complex can be used to better mimic intestinal physiology. Therefore, the aim of this research was to identify the most appropriate in vitro model, and biochemical and molecular markers for assessing the toxicity of NMs to the intestine in vitro. Undifferentiated Caco-2 cells, differentiated Caco-2 cells, Caco-2/HT29-MTX (mucus secreting intestinal model) and Caco-2/Raji B (M cell) co-cultures were used for this study. Copper oxide (CuO) NMs were investigated and copper sulphate (CuO4) included as an ionic control. CuO NMs are useful due to their antimicrobial properties for wood preservation, inks, cosmetics, textiles and food contact materials and their incorporation in these products may enhance oral exposure. CuO NMs and CuSO4, impaired the function of the intestinal barrier (as indicated by a reduction in transepithelial electrical resistance (TEER) and Zonular occludens (ZO-1) staining intensity), and shortened microvilli in all differentiated in vitro intestinal models tested. An increase in interleukin (IL)-8 secretion, upregulation of haem oxygenase (HMOX)1, IL8, metallothionein (MT) 1A and 2A and mucin (MUC) 2 expression were also observed following exposure of all models to CuO NMs and CuSO4. CuO NMs and CuSO4 increased reactive oxygen species (ROS) production in acellular conditions, but only CuSO4 induced ROS production in the cell models. The Caco-2/Raji B co-culture demonstrated the highest level of NM translocation. Silica NMs and montmorillonite nanoclays did not stimulate a toxic response. The toxicity of CuO NMs and CuSO4 was typically 2 fold greater in undifferentiated Caco-2 cells, suggesting that undifferentiated cells may overestimate the toxicity of NMs. Therefore, it is suggested that differentiated Caco-2 cells, Caco-2/HT29-MTX and Caco-2/Raji B co-cultures are powerful in vitro intestinal models and can be used to assess NM toxicity to the intestine. In addition, HMOX1, IL8, MT2A and MUC2 expression, IL-8 protein, TEER measurement, ZO-1 staining and light microscopy to assess cell morphology and viability are presented as biomarkers for investigating the intestinal toxicity of NMs across in vitro models of varied complexity

Evaluation of Physicochemical Properties, Mineral and Heavy Metal Content of Drinking Water Samples in Two Communities in South-East, Nigeria: A Puplic Health Implication

The aim of this study is to evaluate the physicochemical properties, mineral and heavy metal content of drinking water sources in two communities in South-East, Nigeria and discuss its public health implication. The water samples were collected from two wells and two streams respectively in the two communities (Ishiagu and Ugwuaji). The physicochemical parameters, minerals and heavy metal content were analyzed using standard methods. The total acidity, total suspended solid (TSS), biochemical oxygen demand (BOD), nitrate, phosphorous, arsenate, mercury, lead, and cadmium were above both Federal Environmental Protection Agency (FEPA) and United States Environmental Protection Agency (US EPA) standards for drinking water while iron was only above EPA standards. Ishiagu stream had significantly (p<0.05) higher level of most of the physicochemical parameters, minerals and heavy metals followed by Ugwuaji well then, Ishiagu well and Ugwuaji stream had the lowest. The result shows an indication of minerals and heavy metals contamination of the water sources of both communities. Therefore, it is suggested that these water sources are not good for drinking due to the possible health hazards that may arise from the consumption heavy metal and mineral contaminated water. Keywords: Water, minerals, heavy metals, health hazards, physicochemical parameters

Toxicological profile of the aqueous-fermented extract of Musa paradisiaca in rats

Objective: This study was conducted to assess the toxicity profile of the aqueous-fermented extract of Musa paradisiaca in rats. Materials and Methods: In acute toxicity test, the rats of different groups were orally administered with a single dose of 500, 1000, 2000 and 5000 mg/kg of fermented extract of M. paradisiaca. The rats were monitored for behavioral changes, toxicity signs and mortality.  In sub-acute test, the rats were orally administered with fermented M. paradisiaca extract (200, 400 and 800 mg/kg/day) for 14 days. Haematological and serum biochemical parameters were evaluated and histopathological studies of the liver and kidney were done. The study was performed from June to July 2017. Results: Concerning the acute toxicity, no toxicity signs or death were recorded and an LD50 value of >5 g/kg for fermented extract of M. paradisiaca was observed. Regarding the sub-acute toxicity, ingestion of the fermented extract of M. paradisiacacaused no significant effects (