Melatonin Rescues Dimethoate Exposure-Induced Meiotic and Developmental Defects of Porcine Oocytes

Abstract

Dimethoate (DT) is an environmental pollutant widely used in agricultural fields and home gardens. Studies have shown that exposure to DT causes reproductive defects in both male and female animals. However, the effects of DT exposure on oocyte maturation and the approach to counteract it are not yet known. Here, we investigated the toxicity of DT on porcine oocyte maturation and the protective effects of melatonin (MT) on DT-exposed oocytes. DT exposure with 1.5 mM partially inhibited cumulus cell expansion and significantly reduced the rate of first polar body extrusion (pb1) during oocyte maturation. Parthenogenetically activated embryos derived from DT-exposed oocytes could not develop to the 2-cell and blastocyst stage. Furthermore, DT exposure led to a significant increase in the rates of misaligned chromosomes, disorganized spindles, and abnormal actin assembly. DT exposure severely disrupted the distribution patterns of mitochondria in oocytes but did not change the subcellular localizations of cortical granules. Importantly, MT supplementation rescued the meiotic and developmental defects of DT-exposed oocytes through repressing the generation of excessive reactive oxygen species (ROS) and autophagy, and DNA damage accumulation. These results demonstrate that melatonin protects against meiotic defects induced by DT during porcine oocyte maturation.

Epidermal growth factor regulates autophagy activity and endocytosis of yak cumulus cells in a concentration-dependent manner

“…These results indicated that these key regulatory molecules could help yak cumulus cells maintain autophagy and endocytic activity during development. Recently, some studies have pointed out that the addition of melatonin, trehalose and other substances in vitro contributes to oocyte development (33,34), while EGF, as an important paracrine factor in follicles and a commonly used nutritional supplement in vitro culture, plays a crucial role in regulating cumulus cell growth, oocyte maturation and early embryonic development (19,21,23). To further investigate the function of EGF in the regulation of autophagy and endocytosis of cumulus cells, we detected the expression of related genes and proteins in cumulus cells treated with different concentrations of EGF and gefitinib.…”

In-vivo investigation of dimethoate toxicity on serum enzymes, target organs and intestinal tissues of albino rats

“…Most often than not, users do not make reference to the application guidelines in agriculture and public health operation, non use of personal protective clothing and indiscriminate disposal of pesticides containers, inadequate knowledge and awareness of the inherent dangers of pesticides, and absence of monitoring for pesticides residues on locally consumed food have being identified as additional reasons for the reported toxicity of the compound [13,14]. Interestingly, it has been reported that melatonin protects against meiotic defects induced by dimethoate during porcine oocyte maturation, probably by preventing oxidative stress [15].…”