| PART I The Establishment of Rat Gastrointestinal Motility Dysfunction Model After Abdominal Operation And Its MechanismBackground: Early postoperative gastrointestinal motility dysfunction is a usual complication after laparotomy, especially after gastrointestinal operation. It can result in small bowel obstruction, serious infection and a second operation. It also can prolong hospital stay, increase hospital expenditure. At present, most of the researches were focused on the increase of inflammatory facts and the regulation of neuroendocrine system after operation, and our early studies showed that glucocorticoid could decrease blood inflammatory facts and increase the recovery of gastrointestinal motility after abdominal operation. But because of its side effects, glucocorticoid were limited in clinical treatment. So we established the rat gastrointestinal motility dysfunction model for further research.Aim: To establish the rat gastrointestinal motility dysfunction model after abdominal operation and study the mechanism.Method: The abdomina operation mode was established by gastrostomy and partial caecectomy in rat. By measuring inflammatory facts and gastrointestinal hormones, we investigated the machanism of gastrointestinal motility disorders after abdominal operation.24 wistar rats were randomly divided into normal group (n=6), operation group (n=18). Each group was divided into POD 1 group (n=6), POD 3 group (n=6) and POD 6 (n=6) according to the time of sacrifice.On POD 1, POD 3 and POD 6, the rat was sacrificed and gastric emptying rate, small bowel propulsion rate, serum gastrin(GAS), motilin(MTL), IL-1, IL-6, TNF-α, Cox-2 were measured.Results: 1. After partial caecectomy and gastrostomosis of rats, the gastric emptying rate and small bowel propulsion rate were reduced significantly on POD 1 and POD 3 (P<0.01), comparing to the normal group. But on POD 6 there was no difference.2.After partial caecectomy and gastrostomosis of rats, the serum GAS and MTL level were reduced significantly on POD 1 (P<0.01), comparing to the normal group. But on POD 3 and POD 6 there was no difference.3. After partial caecectomy and gastrostomosis of rats, the serum IL-1, IL-6, TNF-αand Cox-2 level were increased significantly on POD 1 and POD3 (P<0.01), comparing to the normal group. But on POD 6 there was no difference.Conclusion: After partial caecectomy in rats, the gastrointestinal mobility was inhibited greatly on POD 1, but on POD 6, the inhibition was disappeared and the gastrointestinal mobility was recovered to normal level. The inhibition was related to the decline of serum MTL level and the elevation of serum IL-1 and Cox-2 level. Serum GAS level decreased on POD 1 and gradually recovered from POD 3 to POD 6. PART II The Effect ofω-3 Fatty Acid on Rat Gastrointestinal Motility After Abdominal OperationBackground: Early postoperative gastrointestinal motility dysfunction is a usual complication after laparotomy, especially after gastrointestinal operation. It can result in small bowel obstruction, serious infection and a second operation. It also can prolong hospital stay, increase hospital expenditure. At present, most of the researches were focused on the increase of inflammatory facts and the regulation of neuroendocrine system after operation, and our early studies showed that glucocorticoid could decrease blood inflammatory facts and increase the recovery of gastrointestinal motility after abdominal operation. But because of its side effects, glucocorticoid were limited in clinical treatment.Because the patients who underwent abdominal operation usually could not take food for a while, enteral nutrion and parenteral nutrition become the necessary nutritional supports.ω-3 fatty acid have already been used in parenteral nutrition. Because of its advantages, including alleviating inflammation, inhibiting the growth of tumor, reducing blood-fat, etc,ω-3 fatty acid becomes a hotspot in domestic and overseas research. But there is no report about its relationship with gastrointestinal mobility after laparotomy.Aim: To study the relationship ofω-3 fatty acid with gastrointestinal mobility after laparotomy and its mechanism of action.Method: By infusing normal saline, intralipid andω-3 fatty acid through gastric tube, we studied the effect of normal saline, intralipid andω-3 fatty acid on rat gastrointestinal motility by investigating the inflammatory facts, the gastrointestinal hormones and the gastrointestinal motility.54 wistar rats were randomly divided into normal saline group (n=18), intralipid group (n=18) andω-3 fatty acid group (n=18). Each group was divided into POD 1 group (n=6), POD 3 group (n=6) and POD 6 (n=6) according to the time of sacrifice.Each day after partial caecectomy and gastrostomosis, the rats were perfused normal saline (12.5ml/d), intralipid (12.5ml/d, 5g/kg·d) andω-3 fatty acid (12.5ml/d, 5g/kg·d) through stomach-tube. On POD 1, POD 3 and POD 6, the rat was sacrificed according to its group, and gastric emptying rate, small bowel propulsion rate, serum gastrin(GAS), motilin(MTL), IL-1, IL-6, TNF-α, Cox-2 were measured.Results:1. On POD 3, the gastric emptying rate and small bowel propulsion rate inω-3 fatty acid group were higher than those in normal saline group and intralipid group, P<0.01, but on POD 1 and POD 6, there was no difference.2. On POD 3, the serum GAS and MTL level inω-3 fatty acid group were higher than those in normal saline group, P<0.01, but there was no difference betweenω-3 fatty acid group and intralipid group. On POD 1 and POD 6, there was no difference between them. This indicates the mechanism thatω-3 fatty acid promotes the recovery of gastrointestinal motility does not lie in the increase of serum GAS and MTL level. The possible reasons are: 1. Different food has different effect on gastrointestinal hormones. Bothω-3 fatty acid and intralipid belong to fatty acid, their effects to stimulating gastrointestinal hormones are similar, but more powerful than normal saline. 2.ω-3 fatty acid and intralipid inhibit the secretion of gastric acid, reduce PH value in stomach, then stimulate the secretion of GAS. 3.ω-3 fatty acid and intralipid can stimulate the secretion of MTL.3. On POD 3, the serum IL-1,IL-6,TNF-α,Cox-2 level inω-3 fatty acid group were lower than those in normal saline group and intralipid group, P<0.05. But on POD 1 and POD 6, there was no difference between them. This indicates thatω-3 fatty acid can decrease serum inflammatory facts level such as IL-1, IL-6, TNF-αand Cox-2 level. Because postoperative inflammation inhibits gastrointestinal mobility significantly,ω-3 fatty acid can accelerate the recovery of gastrointestinal mobility after operation.Conclusion:ω-3 fatty acid can accelerate the recovery of gastrointestinal mobility after caecectomy in rats. Its mechanism of action could be: co-3 fatty acid can decease serum inflammatory facts such as IL-1, IL-6, TNF-αand Cox-2 level, relieve postoperative inflammation.ω-3 fatty acid and intralipid can increase serum GAS, MTL level on POD 3, but comparing to intralipid,ω-3 fatty acid can accelerate the recovery of gastrointestinal mobility and inhibit inflammation after abdominal operation. |
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