Abstract：
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.
OBJECTIVE: 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.
OBJECTIVE: 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.
摘要：
背景：慢性砷暴露会导致神经肌肉疾病和其他健康异常。对DNA和细胞骨架/细胞外基质的损伤是由活性氧（ROS）诱导的内在抗氧化剂消耗（硫醇/尿酸盐）引起的。治疗性螯合剂具有多种副作用。
目的：在大鼠模型中验证（山茶）茶提取物的保护作用以及尿酸（UA）或别嘌醇（尿酸消耗剂）对砷毒性的作用。
方法：山茶（CS干叶），向砷中毒的大鼠补充UA或别嘌呤醇4周。在纯AChE（乙酰胆碱酯酶）上体外测试了纯化的茶黄素及其没食子酸酯，并将其PDB/PubChem3-D结构用于计算机内结合研究。从CS提取物中评估主要化学成分。生化分析,PAGE-酶谱,DNA稳定性彗星分析,在砷暴露的大鼠脑组织中进行HE染色。
结果：暴露于砷的动物表现出运动不稳定的症状，减少内在抗氧化剂（过氧化氢酶/SOD1/尿酸），增加AChE，还有丙二醛.小脑和大脑组织的损伤表现为基质金属蛋白酶（MMP2/9）和DNA损伤（彗星）水平升高。补充别嘌呤醇的组表现出某种程度相似的生化反应。在CS组的脑组织中，尤其是小脑受到了相当大的保护，这从内源性抗氧化剂，DNA和细胞骨架保护以及MMP和AChE的失活中可以看出。目前的研究表明，茶黄素-digalalate（TFDG）对纯化的AChE的抑制作用最高（IC50=2.19µg/ml，结合自由能最低；-369.87kcal/mol），其次是TFMG（IC50=3.86µg/ml，-347.06kcal/mol）表明它们可能恢复胆碱能反应的作用。
结论：UA组的良好反应和同种异体组的不良结局证明了UA作为内源性抗氧化剂的神经保护作用。没食子酸黄酮在神经保护机制中的作用有待进一步研究。
目的：在大鼠模型中验证（山茶）茶提取物的保护作用以及尿酸（UA）或别嘌醇（尿酸消耗剂）对砷毒性的作用。
方法：山茶（CS干叶），向砷中毒的大鼠补充UA或别嘌呤醇4周。在纯AChE（乙酰胆碱酯酶）上体外测试了纯化的茶黄素及其没食子酸酯，并将其PDB/PubChem3-D结构用于计算机内结合研究。从CS提取物中评估主要化学成分。生化分析,PAGE-酶谱,DNA稳定性彗星分析,在砷暴露的大鼠脑组织中进行HE染色。
结果：暴露于砷的动物表现出运动不稳定的症状，减少内在抗氧化剂（过氧化氢酶/SOD1/尿酸），增加AChE，还有丙二醛.小脑和大脑组织的损伤表现为基质金属蛋白酶（MMP2/9）和DNA损伤（彗星）水平升高。补充别嘌呤醇的组表现出某种程度相似的生化反应。在CS组的脑组织中，尤其是小脑受到了相当大的保护，这从内源性抗氧化剂，DNA和细胞骨架保护以及MMP和AChE的失活中可以看出。目前的研究表明，茶黄素-digalalate（TFDG）对纯化的AChE的抑制作用最高（IC50=2.19µg/ml，结合自由能最低；-369.87kcal/mol），其次是TFMG（IC50=3.86µg/ml，-347.06kcal/mol）表明它们可能恢复胆碱能反应的作用。
结论：UA组的良好反应和同种异体组的不良结局证明了UA作为内源性抗氧化剂的神经保护作用。没食子酸黄酮在神经保护机制中的作用有待进一步研究。
