| The colon dysfunction is a frequent complication of diabetesmellitus. It affected the the living conditions of patients seriously. Utilenow it is still unclear about its etiopathogenisis and its regulation factor.As the theory of ICC is the pave cell of the gastrointestinal tract isgradually recognize, more and more evidence reveale that ICC play animportant role in the development of the colon dysfunction.Aim:1. To study the alteration of the quantities and ultrastructure of interstitialcells of Cajal (ICC) in the colon with slow transit motion of diabetesmellitus.2. To study the alteration of the stem cell factor (SCF) in the colon withslow transit motion of diabetes mellitus.3. To study the alteration of the stem cell factor and insulin in the serumwith slow transit motion of diabetes mellitus.4. To study the effect on the ICC and the transit of different dose ofinsulin application.Methods:1. The diabetic rat model was established by single intraperitonealinjection of streptozotocin (STZ) (60mg/kg); the control group was injected with the same dose of citrate buffer solution.①9 rats ofabove two groups were killed at different time (six weeks, eightweeks and ten weeks after injection) and at the same time thegastrointestinal transit rate were measured by activated charcoalsuspension pushing test.②Due to the modle of slow transit haveestablished in 6 weeks after injection, we apply different dose ofinsulin on the rest of the rats(respectively 8U/kg~*d,12U/kg~*d and16U/kg~*d).Then in the ten weeks we killed the all rats and detectedthe gastrointestinal transit rate.2. Samples from proximal colonic tissues were obtained in the all groupsrespectively, the ultrastructure of ICC was observed with conventionalelectron microscopy; the distribution of ICC was observed byimmunohistochemistry, the area of c-kit positive cells was counted bycomputer image analysis.3. Samples from proximal colonic tissues were obtained in the controland diabetes groups respectively in 6 weeks and 8 weeks and 10weeks after injection, the expression of the membrane-bound stemcell factor(M-SCF) in the colon was assessed by Westen-blot,theexpression of the membrane-bound stem cell factor(M-SCF) mRNAand soluble stem cell factor(S-SCF) mRNA in the colon were assessedby Real Time PCR. Samples from the serum of the above all groupswere obtained,the concentration of the soluble stem cell factor(S-SCF)was measured by ELISA and the concentration of the insulin wasmeasured by RIA. Samples from proximal colonic tissues were obtained in the control and diabetes and the low dose applicationgroups respectively in 10 weeks after injection, the expression of theKIT was assessed by Westen-blot.Results:1. Compared with the control groups, the blood glucose(BG) in diabeticrats were increased respectively in 6 weeks and 8 weeks and 10 weeks(p＜0.05), there has the trend of ascend little by little in the diabeticgroups(F=0.023, P＞0.05); the rate of gastrointestinal transit in diabeticrats was delayed significantly (p＜0.05) respectively in 6 weeks and 8weeks and 10 weeks, and there has the trend of descend little by little inthe diabetic groups (F=0.641, P＞0.05).2. The unique characters of ICC in the colon of control group werenumerous small vacuoles scattered along cell membrane, integrated basallamina, abundant mitochondrion, heterochromatism distributed alongnuclear membrane was the major, many gap junctions were found amongICCs and neuron cells and myocyte. In the colon of diabetic ratsrespectively in 6 weeks and 8 weeks and 10 weeks, the number of the gapjunctions were significantly decreased, and the structure of those gapjunctions rested were also damaged; damaged and degenerated organellesespecially in mitochondrion, dissolved cytoplasm and formation ofvacuoles were also found ,and there has the trend of aggravation little bylittle along with the time expenditure.3. Compared with the control group, in the proximal colon of diabetic rats, the area of c-kit positive cells in region of intermuscular plexus wassignificantly decreased (P＜0.05) respectively in 6 weeks and 8 weeksand 10 weeks, and there has the trend of descend little by little in thediabetic groups (F=0.003, P＞0.05)4. Compared with the control group, in the proximal colon of diabeticrats respectively in 6 weeks and 8 weeks and 10 weeks, the level ofM-SCF mRNA and its protein was no significantly alteration(P＞0.05,P＞0.05); the level of S-SCF mRNA was significantly declined (P＜0.05)respectively in 6 weeks and 8 weeks and 10 weeks, and there has thetrend of descend little by little in the diabetic groups (F=2.137, P＞0.05).5. Compared with the control group,the serum S-SCF and insulin weresignificantly declined(P＜0.05, P＜0.05) respectively in 6 weeks and 8weeks and 10 weeks, and there has the trend of descend little by little inthe diabetic groups (F=0.33, P＞0.05 and F=0.093, P＞0.05).6. Compared with the diabetic group, the quantities of ICC(P＜0.05) andits destroyed structure and the gastrointestinal transit rate (P＜0.05) weresignificantly improved in the diabetes with low dose insulin applicationgroup,but there were no significantly improvement in the other diabetesgroup with more insulin application(P＞0.05).Conclusions:1. The rate of gastrointestinal transit was delayed and the blood glucosewas increased in the diabetic rats in 6 weeks after injection which showthat there exit colon dysfunction in the diabetic rats,and this kind of conditions was more prominent in 8 and 10 weeks.2. ICC in the region of intermuscular plexus was considerably decreasedin the proximal colon of diabetic rats and its ultrastructure was seriouslydestroyed. It may play an important role in the pathosis of colondysfunction in the diabetic rats.3. The decline of the level of S-SCF mRNA and its protein and the levelof insulin may be the upstream regulation factors of the damage of theICC quantities and its ultrastructure in the diabetic rats.4. Application of low dose insulin can effectively improved thequantities of ICC and its destroyed structure and the gastrointestinaltransit rate.
|
PDF Full Text Request