Extraction Of Total Polysaccharides From Brassica Rapa L.and Study On Effect Of Prevention Of Acute-hypoxia At High Altitude

Objective: The propose of this study is optimizing the extraction process of polysaccharides of Brassica rapa L.from Tibetan and antioxidant effect.Methods: The effects of extraction temperature,solid-liquid ratio,extraction time and extraction times on the extraction of polysaccharides of Brassica rapa L.were investigated by single factor of influence experiment and response surface methodology.The content of total polysaccharides was examined by the evaluation index of optimization conditions,and the scavenging ability of DPPH· by polysaccharides was studied.Six-week old male of kunming mice with SPF grade were randomly divided into five groups according to the random number table,including control group,hypobaric hypoxia group,and high,medium and low groups of total polysaccharides.The drugs were administered by intragastric administration of 1000mg/kg,500mg/kg and 100mg/kg respectively.The administration groups were acclimatized for three days before entering the hypobaric hypoxia chamber,and the rest were given normal saline.In the hypobaric hypoxia chamber,simulating 4000 m in plateau,the drugs were given continuously for 7 days,and the rest groups were given normal saline.The general behavior of mice was observed during the experiment.After the experiment,the levels of SOD,T-AOC,MDA,GSH-Px),LD,LDH and nitric oxide synthase(NOS)in serum of mice were detected with the kit.The levels of SOD,T-AOC,MDA,GSH-Px,LD,LDH,ATPase in brain and lung were measured with the kit.The damage of hippocampal area and lung tissue was observed by HE staining.Results: The results of both the single factor experiment and response surface methodology showed that the content of total polysaccharide from Brassica rapa L.in the extraction temperature for 100℃,solid-liquid ratio for 20.42 ml/g,extraction time for 3.93 h,extraction times for three times under the condition of extraction yield is the largest.In vitro antioxidant experiments showed that the DPPH· scavenging rate was more than 50% when the total polysaccharide concentration was 5mg/ml.In the whole process of the experiment,the mice in normal group responded sensitively,and had normal diet and activities.From the first to the third day after entering the hypobaric hypoxia chamber,the mice in the control group and the intervention group showed the diet and activities of mice decreased,increase of respiratory rate and decline of insensitive response.From the beginning of the fourth day to the end of the experiment,the diet of hypoxic mice gradually recovered,the level of sensitivity and activities increased.Results of related indicators in serum had been showed thatthe activity of NOS and LDH and the concentration of LD and MDA in the control group were significantly increased(P<0.05),and the activity of SOD,GSH-Px and T-AOC were significantly decreased compared with normal group(P<0.05).With the total polysaccharides of Brassica rapa L.,the activity of NOS,LDH and the concentration of LD and MDA in the high and medium dose groups were significantly decreased(P<0.05),while the activity of GSH-Px was increased(high-dose group:p< 0.05;medium-dose group: P<0.05;low-dose group: P<0.05),the total antioxidant capacity of T-AOC and SOD activity was significantly increased in the high-dose group and the medium-dose group,while there was no significant in the low-dose group.Results of brain and lung related indicators showed thatcontents of MDA and LD and activities of LDH in the brain and lung of the control group were significantly increased compared with the normal group(P<0.05),while the activities of SOD,GSH-Px,T-AOC and ATPase were significantly decreased(P<0.05).With the intervention of total polysaccharides of Brassica rapa L.,the contents of MDA,LD and activities of LDH in the brain and lung were decreased,while the activities of SOD,GSH-Px,T-AOC and ATPase were increased,especially in the high-dose group.Pathological results showed that neurons in the hippocampal CA1 area of the brain of mice in the normal group were nomal with similar alveolar size,clear alveolar interstitium and uniform thickness.In the CA1 area of the control group,the neurons were disordered and decreased,and the intercellular space increased,some neurons had nuclear condensation,alveolar cavity was almost abnormality,and the alveolar space was significantly widened with inflammatory cell infiltration.In the high dose of total polysaccharide group,neurons in the CA1 area were arranged in order with hardly any nuclear condensation,uniform alveolar size and slightly increased alveolar stroma.The neurons in the CA1 region in medium and low dose group was relatively disordered,and the alveolar septal cells was increased,but it was inhibited compared with the model group.Conclusion: The total polysaccharides of Brassica rapa L.play the role in anti-hypoxia at high altitude,which can protect the brain and lungs of mice at high altitude by enhancing capacity of antioxidant of organism,reducing oxygen radical damage,and regulating energy metabolism to play an anti-hypoxia role at the plateau.