| As the global climate is gradually warming,heat stress occurs frequently under modern high-density farming conditions.It has become an important factor affecting the production performance of livestock and poultry in summer,resulting in reduced production performance,lower survival rate,and lower meat product quality,etc.The economic benefits of households have been severely lost.Animal intestines are extremely sensitive to heat stress and their injuries are the most serious.Therefore,the search for traditional Chinese medicine for preventing and treating the effects of heat stress on the intestine has become a research hotspot.The Portulaca oleracea L.is a medicinal and food homologous herb,which has the functions of clearing away heat and detoxification,dispersing blood and reducing swelling,cooling blood and stopping dysentery.Studies have shown that purslane has a good anti-stress effect,and also has a significant effect in recovering intestinal mucosal damage.However,the effect and specific mechanism of purslane on the prevention and treatment of heat stress are still unclear,and the effects of heat stress on the intestinal structure,absorption function and intestinal flora of mice have not been reported.Therefore,this experiment focuses on the protective effect and mechanism of Aqueous Extract of Portulaca oleracea L.against heat stress-induced intestinal damage in mice,providing a theoretical basis for the widespread application of purslane in animal husbandry.The experiment used 80 Kunming mice randomly divided into 4 groups(n=20),namely blank control group(Control,C),heat stress group(Heat stress,HS),and the aqueous extract of Portulaca oleracea L.group(AEP),Vitamin C(Vc).After 7 days of adaptive feeding,the mice entered the formal experiment,and the group C was placed in(25 ± 1)℃ environment;the mice in the HS group,AEP group,and Vc group were placed in the daytime ambient temperature(30±1)Reared under the condition of ℃,put the mice into the(40 ± 1)℃ biochemical incubator for heat stress treatment at 14:00-14:30 every day for 0.5 h,and control the temperature at(28±1)℃ at night.During stress,there is no limit to the amount of food and water consumed,and continuous heat stress stimulation for 6 days.After the high temperature stimulation,the mice were all placed in(25±1)℃ environment to start the drug treatment,and were given by intragastric administration at 9 am every day,in which the AEP group was given 2 g/mL purslane water extract 0.2 mL/20g·BW,group Vc was given 500 mg/kg vitamin C 0.2 mL/20 g · BW,group C and HS were given an equal volume of saline for 7 days.Blood was collected from the orbital sinus on the 3rd and 7th day of intragastric administration.After the mice were sacrificed,the jejunum,cecum and their contents and liver were collected.HE staining method was used to observe the histopathological changes of the jejunum mucosa in each test group;the phloroglucinol method was used to detect the content of D-xylose in the mouse serum;the ELISA method was used to detect the SOD,GSH-PX and MDA in the liver homogenate of the mice Content,serum HSP70 content;use glucose oxidase method to detect glucose content in mouse serum;immunohistochemical method to detect the expression level of HSP70,ZO-1,SGLT1 and GLUT2 in jejunum mucosa;qRT-PCR method to detect mice The relative transcript levels of HSP70,ZO-1,SGLT1 and GLUT2 mRNA in jejunum mucosa;16S rRNA sequencing was used to detect the biodiversity of cecum.The results showed that compared with group C,the height of jejunal mucosal villi in the HS group was significantly reduced(P<0.01);the serum D-xylose content and glucose content were reduced(P<0.01);SOD and GSH-in liver tissue homogenate Elevation of PX and MDA(P<0.01);HSP70 content in serum increased significantly(P<0.01);HSP70 expression level in jejunal mucosa and relative transcription level of mRNA were significantly increased(P<0.01);jejunum mucosa The expression levels of ZO-1,SGLT1 and GLUT2 and the relative transcript levels of mRNA showed a decreasing trend(P<0.05);the abundance of Clostridium lenti and Lactobacillus in the intestine of mice was significantly reduced(P<0.05).Helicobacter pylori The content of Helicobacter increased significantly(P<0.05).Compared with mice in HS group,the height of jejunal villi in AEP group and Vc group was significantly increased(P<0.01);serum D-xylose and glucose levels were significantly increased(P<0.05);in AEP group The content of MDA in the middle liver decreased significantly(P<0.05).Although the content of SOD and GSH-PX increased,there was no significant difference compared with the HS group(P>0.05).which was consistent with the results of the Vc group;serum HSP70 The content was significantly reduced(P<0.01);the expression level of HSP70 and the relative transcription level of mRNA in the jejunal mucosa were significantly reduced(P<0.05);the expression level of ZO-1,SGLT1 and GLUT2 in the jejunal mucosa and the relative transcription of mRNA The level has increased.the difference is significant(P<0.05):the abundance of predominant bacterial groups in mice is increased.such as Lactobacillus,Clostridium lentum,and Streptococcus,and harmful bacteria such as Helicobacter and Helicobacter pylori The abundance is significantly reduced.Conclusion:The test results show that heat stress can cause oxidative stress damage in the jejunum of mice,disorder of intestinal flora,and reduced absorption of nutrients.the aqueous extract of Portulaca oleracea L.can increase the expression of ZO-1 in the jejunum mucosa of heat-stressed mice,thereby consolidating the tight junction structure of intestinal mucosa epithelial cells;it can also increase the serum D-xylose content and glucose content by increasing the jejunum The expression levels of SGLT1 and GLUT2 in the mucosa can effectively improve the absorption function of the damaged jejunum;and can reduce the oxidative stress response of heat-stressed mice and reduce the HSP70 in heat-stressed mice by eliminating free radicals and peroxides Express the amount and make it closer to normal.At the same time,the aqueous extract of Portulaca oleracea L.can increase the abundance of predominant bacterial groups in the intestinal tract of heat-stressed mice,such as Lactobacillus,Clostridium lentum,and Streptococcus,etc.,and reduce the number of harmful bacteria such as Helicobacter pylori and Phytophthora.It can recover the damage caused by heat stress to the intestine of mice as a whole and achieve good anti-heat stress effect. |
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