| Oxygen is the key substance for the body to maintain its life activities and its normal metabolism.It is generally believed that areas with an altitude of more than3000 m are hypoxic areas.Oxygen concentration in these areas are below normal,which can cause damage to animal tissues and organs.Cichoric acid is an effective immunoactive substance in plants such as Echinacea,CA can not only improve immunity,anti-inflammatory,resist virus invasion and reduce oxidative damage,but also enhance the hypoxic adaptability of Yaks in alpine areas.However,there are few studies on CA hypoxic adaptability in SD rats.Therefore,60 SD rats were selected as the test object,carry out the SD rats feeding experiment under hypoxic environment（adaptation period for 2 weeks,formal feeding for 7 weeks）,gavage different concentrations of CA（10 mg/kg,20 mg/kg,40 mg/kg）to SD rats,and clarify the effect of CA on hypoxic adaptability of SD rats.After collecting the hearts of SD rats,the HWI,LVMI and RVMI were calculated,and the content of ANP and BNP were measured.The hematological indexes of SD rats were measured by blood collection from jugular vein and abdominal aorta.Activities of oxidative stress indexes and energy metabolism indexes in myocardial tissue of SD rats were measured by Elisa.The m RNA and protein expression of hypoxia adaptation genes in myocardial tissue of SD rats were detected by q RT-PCR and immunohistochemistry.Results are as follows:（1）Results of myocardial tissue structure showed that,compared with control group,CA obviously up-regulated HWI and LVMI（P<0.05）,BW,RVMI,ANP and BNP contents were not significant（P>0.05）.Results between different test groups showed,40 mg/kg group obviously increased HWI and LVMI（P<0.05）,BW,RVMI,ANP and BNP contents were not significant（P>0.05）.（2）Results of hematological indexes showed that,compared with control group,CA obviously up-regulated the blood routine indexes RBC,HCT,Hb,MCHC and MCH（P<0.05）,and obviously reduced MCV,PLT and PCT（P<0.05）.CA obviously increased the blood gas indexes PO2,SO2,and p H（P<0.05）,and obviously reduced the concentrations of PCO2,AG,TCO2（P<0.05）.CA obviously reduced the blood biochemical indexes LDH and CK（P<0.05）.Results between different test groups showed,40 mg/kg group obviously up-regulated the contents of RBC,HCT,Hb,MCHC and MCH（P<0.05）,and obviously reduced the contents of PLT,PCT,PCO2,AG,LDH,CK（P<0.05）.（3）Results of oxidative stress indexes and energy metabolism indexes showed that,compared with control group,CA obviously reduced ROS and MDA activities,and obviously up-regulated SOD,GSH-px,CAT activities,and mitochondrial respiratory chain complex I and III（P<0.05）.CA obviously up-regulated Na+-K+-ATPase,Ca2+-ATPase activities（P<0.05）.Results between different test groups showed,40 mg/kg group obviously reduced ROS,MDA activities（P<0.05）,and obviously increased SOD,GSH-px,CAT,respiratory chain complex III,Na+-K+-ATPase and Ca2+-ATPase activities（P<0.05）.（4）Results of hypoxia adaptation genes showed that,compared with control group,CA obviously up-regulated HIF-1α,EPO and VEGF m RNA and protein expression（P<0.05）.Results between different test groups showed,40 mg/kg group CA obviously up-regulated HIF-1α,EPO and VEGF m RNA and protein expression（P<0.05）.In conclusion,Echinacea extract-CA can enhance the hypoxic adaptability of SD rats at high altitude by regulating the metabolism of blood and myocardial tissue of SD rats,and under the conditions of this test the optimum concentration of CA is40 mg/kg. |
