Melatonin attenuates arsenic induced nephropathy via the regulation of oxidative stress and inflammatory signaling cascades in mice

Melatonin attenuates caspase-dependent apoptosis in the thoracic aorta by regulating element balance and oxidative stress in pinealectomised rats

The aim of this study was to explain the possible mechanisms by which melatonin deficiency results in cardiovascular injury and to investigate the effects of melatonin administration on important signalling pathways and element equilibrium in the thoracic aorta (TA). For this purpose, we analysed the cellular and molecular effects of melatonin deficiency or administration on oxidative stress, DNA damage, molecular chaperone response, and apoptosis induction in TA tissues of pinealectomised rats using ELISA, RAPD, qRT-PCR, and Western blot assays. The results showed that melatonin deficiency led to an imbalance in essential element levels, unfolded or misfolded proteins, increased lipid peroxidation, and selectively induced caspase-dependent apoptosis in TA tissues without significantly affecting the Bcl-2/BAX ratio (2.28 in pinealectomised rats, 2.73 in pinealectomised rats treated with melatonin). In pinealectomised rats, the genomic template stability (80.22%) was disrupted by the significantly increased oxidative stress, and heat shock protein 70 (20.96-fold), TNF-α (1.73-fold), caspase-8 (2.03-fold), and caspase-3 (2.87-fold) were markedly overexpressed compared with the sham group. Melatonin treatment was protective against apoptosis and inhibited oxidative damage. In addition, melatonin increased the survivin level and improved the regulation of element equilibrium in TA tissues. The results of the study indicate that melatonin deficiency induces TNF-α-related extrinsic apoptosis signals and that the administration of pharmacological doses of melatonin attenuates cardiovascular toxicity by regulating the increase in the rate of apoptosis caused by melatonin deficiency in TA tissue of Sprague–Dawley rats.

Taurine ameliorates oxidative stress induced inflammation and ER stress mediated testicular damage in STZ-induced diabetic Wistar rats

One of the major consequences of diabetes is reproductive dysfunction but the fundamental mechanisms are still poorly known. The objective of the present study was to explore the beneficial role of taurine against streptozotocin induced testicular dysfunctions in diabetic male Wister rats and understanding the underlying intricate molecular mechanisms. Exposure to streptozotocin (50 mg kg^-1 body weight, i.p., once) elevated blood glucose level, induced testicular histological alterations and reduced testis-to-body weight ratio, serum testosterone, testicular markers and activity of antioxidant enzymes. Generation of ER stress (increased expression of calpain-1, caspase-12 and upregulation of CHOP, GRP78 via eIF2α signaling), translocation of NF κB in the nucleus (leading to the upregulation in the levels of inflammatory cytokines), activation of mitochondria dependent apoptotic pathway and DNA fragmentation were revealed from this study. However, administration of taurine at a dose of 100 mg kg^-1 body weight for 6 weeks post diabetic induction, successfully ameliorated all these adverse effects. Thus, taurine, as a potential therapeutic agent, may hold promise in preventing oxidative and ER stress mediated diabetic testicular complications in rats.

Responses of Transgenic Melatonin-Enriched Goats on LPS Stimulation and the Proteogenomic Profiles of Their PBMCs

The anti-inflammatory activity of melatonin (MT) has been well documented; however, little is known regarding endogenously occurring MT in this respect, especially for large animals. In the current study, we created a MT-enriched animal model (goats) overexpressing the MT synthetase gene Aanat. The responses of these animals to lipopolysaccharide (LPS) stimulation were systematically studied. It was found that LPS treatment exacerbated the inflammatory response in wild-type (WT) goats and increased their temperature to 40 °C. In addition, their granulocyte counts were also significantly elevated. In contrast, these symptoms were not observed in transgenic goats with LPS treatment. The rescue study with MT injection into WT goats who were treated with LPS confirmed that the protective effects in transgenic goats against LPS were attributed to a high level of endogenously produced MT. The proteomic analysis in the peripheral blood mononuclear cells (PBMCs) isolated from the transgenic animals uncovered several potential mechanisms. MT suppressed the lysosome formation as well as its function by downregulation of the lysosome-associated genes Lysosome-associated membrane protein 2 (LAMP2), Insulin-like growth factor 2 receptor (IGF2R), and Arylsulfatase B (ARSB). A high level of MT enhanced the antioxidant capacity of these cells to reduce the cell apoptosis induced by the LPS. In addition, the results also uncovered previously unknown information that showed that MT may have protective effects on some human diseases, including tuberculosis, bladder cancer, and rheumatoid arthritis, by downregulation of these disease-associated genes. All these observations warranted further investigations.