| Objective: Diabetes mellitus(DM) affects virtually every organ system inthe body and the degree of organ involvement depends on the duration andseverity of the disease. Gastrointestinal (GI) involvement can present withgastroparesis, which is one of the commonest gastrointestinal complications ofdiabetes mellitus with the characteristics of gastric motility disorder anddelayed gastric emptying. Diabetic gastroparesis manifests as early satiety,bloating, nausea, vomiting and erratic glycemic control. About27%-65%ofpatients in type1diabetes have delayed gastric emptying and gastric motilitydisorder existed in30%of patients in type2diabetes. The incidence ofgastroparesis is higher in women. Gastroparesis typically develops after atleast10years of diabetes, and these patients generally have evidence ofautonomic dysfunction. Although the exact mechanism of DGP is unknown, anumber of contributing factors have been proposed, including hyperglycemia,vagal dysfunction, loss of neurons in the enteric nervous system (ENS),interstitial cells of Cajal (ICC) network disturbances, smooth muscle lesionsand microcirculation disorder. Brownlee reported that high glucose promptedmitochondria to produce too much super oxide anion and oxidative stress wasthe common mechanism of diabetic complications. The recent researchesfounded that oxidative stress and its mediated apoptosis participated thedevelopment of diabetic complications including diabetic nephropathy,diabetic retinopathy and diabetic neuropathy. However, there were fewresearches about the relationship of oxidative stress and apoptosis and theirsignal transduction pathway in DGP. The prescription containing astragalus,prepared rehmannia root, turtle shell, centella, salvia, rhubarb, lumbricus,leech, Poria and fructus amomi showed good effect to cure DGP by replenishing Qi and Yin, eliminating stasis and dredging meridians. In thisresearch, we studied the changes of gastric emptying rate，the apoptosis ofgastric smooth muscle cells and the changes in expression ofapoptosis-regulated genes under oxidative stress resulted from high glucose.Meanwhile，we demonstrated the protecting effects of herbs of replenishing Qiand Yin, eliminating stasis and dredging meridians acid on DGP and explorethe related mechanism, providing new theoretical bases for treatments ofDGP．Methods: Thirty Sprague-Dawley(SD)male rats，with body weight of201-205grams were randomly divided into3groups: normal control group,the model group and traditional Chinese medicine group after adaptive feedingfor2weeks. Except the normal control group, the model group and Chinesemedicine group were injected with streptozotocin(STZ)sterile solution(50mg/kg) to establish the model of diabetic rats, while normal control groupwas intraperitoneally injected equal volume of citrate buffer solution.72h later,blood glucose≥16.7mmol/L were taken as the standard model. The rats intraditional Chinese medicine groups were treated by intragastricadministration with the herbs of replenishing Qi and Yin, eliminating stasisand dredging meridians10ml/(kg·d), while the rats in normal control groupand diabetic model group were treated by intragastric administration with theequal volume of normal saline by gavage, once a day for6weeks. In the sixthweek, the rats were treated by intragastric administration with phenol redsolution (500mg/L)2ml. After the anesthesia by intraperitoneal injection of8%2ml/kg amobarbital sodium, opened the abdominal cavity, ligated cardiaand pylorus, removed the rat stomach and measured gastric emptying rate(GER) by phenol red. Parts of stomach tissue were taken in4%paraformaldehyde, then apoptotic gastric smooth muscle cell were identifiedby terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling(TUNEL). Parts of stomach tissue were taken in the low temperature of-80℃.The changes of malondialdehyde(MDA) content and the activity of superoxidedismutase (SOD) in gastric were detected. Real-time PCR was applied to detect the expressions of HO-1, Bcl-2and Bax mRNA.Results：1Comparison of the general condition of rats in three groupsRats in normal control group had significant increase in weight. Theywere in good health spiritually, fur lustrous, quick response. During the wholestudy there were no adverse reactions and they gained weight. However, therats injected with STZ appeared gradually polyphagia, polydipsia, polyuria,unresponsive with losing weight. Two rats died in this group during theexperiment. The rats in traditional Chinese medicine group were in bettercondition than these in diabetic model group without death.2Changes of body weight and blood glucose of rats in each groupResults showed: compared with the normal control group, the bodyweight in the model group and traditional Chinese medicine group wereobviously lower (P<0.05). No significant differences were found in bodyweight of the model group and traditional Chinese medicine group (P>0.05).The levels of blood glucose in the model group and traditional Chinesemedicine group were increased obviously in comparison with the normalcontrol group (P<0.05); compared with the model group, blood glucose inChinese medicine group were decreased obviously(P<0.05).3Comparison of gastric emptying rate in three groupsThe gastric emptying rate in the model group and traditional Chinesemedicine group were reduced significantly compared with the normal controlgroup (P<0.05); gastric emptying rate of traditional Chinese medicine groupwere significantly increased than the model group (P<0.05).4Comparison of SOD activities and MDA content in three groupsSOD activities and MDA content in gastric tissue in three groupsindicated: SOD activities were decreased obviously in the model group andtraditional Chinese medicine group in comparison with normal control group(P<0.05), while SOD activities were higher in traditional Chinese medicinegroup than the model group (P<0.05). Compared with the normal controlgroup, the gastric MDA content were elevated in the model group and traditional Chinese medicine group (P<0.05); compared with the model group,the gastric MDA content in Chinese medicine group were decreased obviously(P<0.05).5Comparison of the expression of HO-1proteinThe rats HO-1content indicates: the level of HO-1protein wereincreased in model group in comparison with normal control group (P<0.05);compared with the model group, the content of HO-1protein markedly rise intraditional Chinese medicine group (P<0.05).6Comparison of the expression of HO-1mRNACompared with the normal control group, the expression of HO-1mRNAwere elevated in the model group (P<0.05); compared with the model group,there was a growth in the expression of HO-1mRNA obviously in traditionalChinese medicine group (P<0.05).7Comparison of apoptotic gastric smooth muscle cellsIn normal control group there were few apoptotic gastric smooth musclecells, while the apoptotic index of gastric smooth muscle cells weresignificantly increased in the model group and traditional Chinese medicinegroup (P<0.05); compared with model group, the apoptotic index of gastricsmooth muscle cells were significantly reduced in traditional Chinesemedicine group (P<0.05)．8Comparison of the expression of Bcl-2and Bax mRNA as apoptosisregulated genes in different groupsLevels of Bcl-2and Bax mRNA in gastric tissue showed: compared withnormal control group, the level of Bcl-2mRNA in gastric tissues of the modelgroup and traditional Chinese medicine group were decreased (P<0.05);compared with the model group, the level of mRNA in traditional Chinesemedicine group mentioned above were increased (P<0.05).The expression of Bax mRNA in gastric tissues of the model group wereincreased in comparison with normal control group (P<0.05), while there wereno obvious distinction in the expression of Bax mRNA of normal controlgroup and traditional Chinese medicine group(P>0.05).Compared with the model group, the expression of Bax mRNA in traditional Chinese medicinegroup were decreased(P<0.05)．Conclusions:1There are evident gastric motility disorder in the diabetic gastroparesis.Herbs of replenishing Qi and Yin, eliminating stasis and dredging meridianscan obviously lower blood glucose and improve gastric motility; it’s a welltreatment for diabetic gastroparesis.2The oxidative stress is enhanced in gastric tissues of diabeticgastroparesis rats. Oxidative stress and its mediated apoptosis in gastricsmooth muscle cells prove to be central in the development of diabeticgastroparesis.3Herbs of replenishing Qi and Yin, eliminating stasis and dredging meridiansplay an active role in improving gastric motility by decreasing oxidative stressand inhibiting apoptosis of gastric smooth muscle cells, which afford newtheoretical bases for treating the diabetic gastroparesis．... |
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