Measurement of the Effects of Metals on Taxis-to-Food Behavior in Caenorhabditis elegans

Toxicity study of mineral medicine haematitum

ETHNOPHARMACOLOGICAL RELEVANCE

Haematitum, a time-honored mineral-based Chinese medicine, has been used medicinally in China for over 2000 years. It is now included in the Chinese Pharmacopoeia and used clinically for treating digestive and respiratory diseases. The Chinese Materia Medica records that it is toxic and should not be taken for a long period, but there are few research reports on the toxicity of Haematitum and its potential toxicity mechanisms.

AIM OF THE STUDY

This study aimed to evaluate the toxicity of Haematitum and calcined Haematitum, including organ toxicity, neurotoxicity, and reproductive toxicity. Further, it is also necessary to explore the mechanism of Haematitum toxicity and to provide a reference for the safe clinical use of the drug.

MATERIALS AND METHODS

The samples of Haematitum and calcined Haematitum decoctions were prepared. KM mice were treated with samples by gavage for 10 days, and lung damage and apoptosis were assessed by HE staining and TUNEL staining of lung tissues respectively. Metabolomics analysis was performed by HPLC-MS. Metallomics analysis was performed by ICP-MS. In addition, C. elegans was used as a model for 48 h exposure to examine the neurotoxicity and reproductive toxicity-related indices of Haematitum, including locomotor behaviors, growth and development, reproductive behaviors, AChE activities, sensory behaviors, apoptosis, and ROS levels.

RESULTS

The use of large doses of Haematitum decoction caused lung damage in mice. Neither calcined Haematitum decoction nor Haematitum decoction at clinically used doses showed organ damage. Metabolomics results showed that disorders in lipid metabolic pathways such as sphingolipid metabolism and glycerophospholipid metabolism may be important factors in Haematitum-induced pulmonary toxicity. High doses of Haematitum decoction caused neurological damage to C. elegans, while low doses of Haematitum decoction and calcined Haematitum decoction showed no significant neurotoxicity. Decoction of Haematitum and calcined Haematitum did not show reproductive toxicity to C. elegans. Toxicity was also not observed in the control group of iron (Ⅱ) and iron (Ⅲ) ions in equal amounts with high doses of Haematitum.

CONCLUSIONS

Haematitum is relatively safe for routine doses and short-term use. Calcination can significantly reduce Haematitum toxicity, and this study provides a reference for safe clinical use.

Caenorhabditis elegans as an in vivo model for the identification of natural antioxidants with anti-aging actions

Natural antioxidants have recently emerged as a highly exciting and significant topic in anti-aging research. Diverse organism models present a viable protocol for future research. Notably, many breakthroughs on natural antioxidants have been achieved in the nematode Caenorhabditis elegans, an animal model frequently utilized for the study of aging research and anti-aging drugs in vivo. Due to the conservation of signaling pathways on oxidative stress resistance, lifespan regulation, and aging disease between C. elegans and multiple high-level organisms (humans), as well as the low and controllable cost of time and labor, it gradually develops into a trustworthy in vivo model for high-throughput screening and validation of natural antioxidants with anti-aging actions. First, information and models on free radicals and aging are presented in this review. We also describe indexes, detection methods, and molecular mechanisms for studying the in vivo antioxidant and anti-aging effects of natural antioxidants using C. elegans. It includes lifespan, physiological aging processes, oxidative stress levels, antioxidant enzyme activation, and anti-aging pathways. Furthermore, oxidative stress and healthspan improvement induced by natural antioxidants in humans and C. elegans are compared, to understand the potential and limitations of the screening model in preclinical studies. Finally, we emphasize that C. elegans is a useful model for exploring more natural antioxidant resources and uncovering the mechanisms underlying aging-related risk factors and diseases.

Neurotoxicity Evaluation of Nanomaterials Using C. elegans: Survival, Locomotion Behaviors, and Oxidative Stress

Nanomaterials are broadly used in a variety of industries and consumer products. However, studies have demonstrated that many nanomaterials, including metal-containing nanoparticles and nanoplastics, have neurotoxic effects. Caenorhabditis elegans (C. elegans) is a widely used model organism with numerous advantages for research, including transparency, short life span, well-characterized nervous system, complete connectome, available genome, and numerous genetic tools. C. elegans has been extensively used to assess the neurotoxicity of multiple chemicals via survival assays, behavioral tests, neuronal morphology studies, and various molecular and mechanistic analyses. However, detailed protocols describing general assays in C. elegans to examine the neurotoxic effects of nanomaterials are limited. Here, we describe protocols for assessing nanomaterial neurotoxicity in C. elegans. We describe the steps for exposure and subsequent evaluation of survival, locomotion behavior, and oxidative stress. Survival and locomotion behavior are measured in wild-type N2 strains to assess acute neurotoxicity. Oxidative stress is used as an endpoint here since it is one of the most predominant and common changes induced by nanomaterials. VP596 nematodes, which express GFP upon activation of skn-1 (the worm homolog of Nrf2), are evaluated for assays of oxidative stress in response to test nanomaterials. These assays can be readily used to quickly examine the neurotoxicity of nanomaterials in vivo, laying the foundation for mechanistic studies of nanomaterials and their impacts on health and physiology. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Exposure of C. elegans to nanomaterials Basic Protocol 2: Survival assessment Basic Protocol 3: Assessment of locomotion behavior Basic Protocol 4: Analysis of oxidative stress.