Study On The Colons And Its Microbacterium Of The Rats Chronically Administered With Rhubarb

Rhubarb,a traditional Chinese herb,has been used in clinics as laxative for thousands of years.It has been known that rhubarb plays laxative function through active metabolites produced in the intestinal by enzymes.Clinical studies indicated that long-term usage of rhubarb anthraquinone might result in a series of side effects including drug resistance and Melanosis Coli?MC?formation.However,it is still unknown with the toxic materials and mechanisms.In this study,long-term usage of Rhubarb anthraquinone was mimic in the SD rats.HPLC technology was used to analyze the metabolites remaining in the rat feces and in the in vitro intestine culture system;GC method was used to detect the content of Short-Chain Fatty Acids?SCFAs?in the rats fecal solution;At the same time,the rats were observed with a series of physiological indexes during the experiments.Finally,it would be clarified with the toxic materials resulting in the damage on the colon and the changes on the intestinal microbacterium.?1?Rhubarb anthraquinone?RA?was prepared and analyzed by HPLC which could be used to simultaneously determine the content of conjunct anthraquinones and free form of anthraquinones.The content of Sennoside A?SA?was analyzed and was 8.99%?g/g?in the RA.?2?The rats were fed with the RA for three months.In order to maintain grade 2³diarrhea in rats,the dosage was increased 10 times.The rats showed diarrhea resistance and MC formation in the colons in the end of the experiments.It provides a reliable animal model for later sample collection.?3?The rats were observed with the changes on body weight,fecal water content and OD values of the fresh fecal solution collected during the feeding.There was a decrease on the body weight,fecal water loss rate and OD value in the RA-treated rats.There was a significant increase on the heart,colon and stomach organ indexes,but decrease on the spleen and prostate organ index in the RA-treated rats.Observation on histopathology indicated that the colons of the RA-treated rats showed severe colonic goblet cell damage,glandular destruction,large amount of inflammatory cell infiltration in the crypt structure,and obvious melanin granule deposition.?4?The fresh feces and serum samples were regularly collected from the rats during the experiments.The metabolites in feces and serum were detected by using HPLC.The results showed that the content of rhein was gradually increased in the feces and serum collected from the RA-treated rats.?5?The fresh feces were regularly collected from the rats and were cultured with the SA to produced the metabolites.The metabolites produced were detected by HPLC.There were five metabolites including M₂?aloe emodin?,M₃?rhein?,M₁,M₄ and M₅.It was found that the degradation rate of SA in intestinal bacteria solution collected from the RA-treated rats was significantly higher than that from the normal control rats.This suggested that the long-term usage of the rhubarb might promote the the degradation rate leading to the accumulation of metabolites in the colons.?6?The fresh feces were regularly collected from the rats and analyzed with the the content of short-chain fatty acids?SCFAs?by using GC method.The results showed that there were significant higher contents in the normal control rats with acetic acid,propionic acid and butyric acid.In summary,the long-term usage of rhubarb anthraquinone could result in the accumulation of rhein in the rat colon and the changes on the content of acetic acid?propionic acid and butyric acid.This might be responsible for the drug resistance and MC formation.