Serum Proteomic Profiling Analysis of Rats Chronically Exposed to Arsenic

Arsenic Induced Oxidative Neural-Damages in Rat are Mitigated by Tea-Leave Extract via MMPs and AChE Inactivation, Shown by Molecular Docking and in Vitro Studies with Pure Theaflavin and AChE

BACKGROUND

Chronic arsenic-exposure causes neuromuscular disorders and other health anomalies. Damage to DNA and cytoskeletal/extracellular matrix is brought on by reactive-oxygen-species (ROS)-induced intrinsic antioxidant depletion (thiols/urate). Therapeutic chelating-agents have multiple side-effects.

OBJECTIVES

The protection of (Camellia sinensis) tea-extract and role of uric-acid (UA) or allopurinol (urate-depletor) on arsenic-toxicity were verified in rat model.

METHODS

Camellia sinensis (CS dry-leaves), UA or allopurinol was supplemented to arsenic-intoxicated rats for 4-weeks. Purified theaflavins and their galloyl-ester were tested in-vitro on pure AChE (acetylcholinesterase) and their PDB/PubChem 3-D structures were utilized for in-silico binding studies. The primary chemical components were evaluated from CS-extracts. Biochemical analysis, PAGE-zymogram, DNA-stability comet analysis, HE-staining was performed in arsenic-exposed rat brain tissues.

RESULTS

Animals exposed to arsenic showed symptoms of erratic locomotion, decreased intrinsic antioxidants (catalase/SOD1/uric acid), increased AChE, and malondialdehyde. Cerebellar and cerebrum tissue damages were shown with increased levels of matrix-metalloprotease (MMP2/9) and DNA damage (comets). Allopurinol- supplemented group demonstrated somewhat similar biochemical responses. In the CS-group brain tissues especially cerebellum is considerably protected which is evident from endogenous antioxidant and DNA and cytoskeleton protection with concomitant inactivation of MMPs and AChE. Present study indicates theaflavin-digallate (TFDG) demonstrated the highest inhibition of purified AChE (IC50 = 2.19 µg/ml with the lowest binding free-energy; -369.87 kcal/mol) followed by TFMG (IC50 = 3.86 µg/ml, -347.06 kcal/mol) suggesting their possible restoring effects of cholinergic response.

CONCLUSIONS

Favorable responses in UA-group and adverse outcome in allo-group justify the neuro-protective effects of UA as an endogenous antioxidant. Role of flavon-gallate in neuro protection mechanism may be further studied.

Effects of arsenic exposure on lipid metabolism: a systematic review and meta-analysis

Lipid metabolism dysfunction is a risk factor for cardiovascular diseases. Reportedly, arsenic exposure could affect lipid metabolism, but this finding remains controversial. Herein, we updated and reevaluated evidence regarding the relationship between arsenic exposure and lipid metabolism. Electronic and manual searches were performed to determine the effect of arsenic exposure on lipid metabolism from inception up to 30 November 2019. Overall, five studies were included in our meta-analysis. Two reviewers independently extracted information. Standardized mean difference (SMD) and 95% confidence intervals (CI) were used to analyze the combined effects of four indicators related to lipid metabolism (total cholesterol [TC], triglyceride [TG], high-density lipoprotein [HDL], low-density lipoprotein [LDL]). Afterwards, subgroup and sensitivity analyses were performed to explore the source of heterogeneity. Publication bias was tested using funnel plots and Begg's test. In this study, we observed that arsenic exposure can affect lipid metabolism by reducing serum HDL levels and increasing serum LDL levels. Following subgroup analysis, the arsenic concentration appeared to affect lipid metabolism. Funnel plot and Begg's test suggested no asymmetry. In conclusion, we recommend that potential influencing factors, including age, exposure time, and multiple concentration gradients, should be considered to further explore the relationship between arsenic exposure and lipid metabolism.