Experimental Study Of The Effects Of Curcumin On The Activity Of Contraction Or Relaxation In Isolated Duodenal Smooth Muscle Of Mice

Background:Curcumin is widely used for the anti-inflammatory disease of the gastrointestinal tract because of its anti-inflammatory and antioxidant effects. Systemic administration of Curcumin can significantly lessen the retention of food in gastrointestine and ameliorate the peristaltic dysfunction of mice, which has been shown in the previous studies in our laboratory.Objective:Curcumin was incubated with the isolated duodenal smooth muscle of mice in order to observe the direct effects of Curcumin on the gastrointestinal activity, and the effects was further compared with that of the systemic administration of Curcumin in mice to identify the direct effects of Curcumin on the peristaltic activity of gastrointestine.Methods:The duodenal smooth muscle of mice were removed and made into smooth muscle strips. The strips was suspended in the37℃bath contains Krebs solution and maintained continuously gas with95%O2and5%CO2. The tension changes of duodenum smooth muscle were measured and recorded through the signal acquisition and processing system. Then doing the following experiments:1. Incubate the different concentration of Curcumin (10μmol/L-20μmol/L) with the strip and to record the spontaneous contractile amplitude of duodenal smooth muscle;2. Add the acetylcholine (Ach) to induce contraction, then incubate with curcumin(20μmol/L) to record the changes of contractile amplitude of duodenal smooth muscle;3. Add the epinephrine to induce relaxation, then incubate with Curcumin (20μmol/L) to record the changes of contractile amplitude of duodenal smooth muscle;4. Add the adrenaline to induce relaxation, and then incubate with Curcumin (20μmol/L) to record the changes of contractile amplitude of duodenal smooth muscle. By introgastric administration of Curcumin (0.2ml,200mg/kg) to mice, the food residual rate in stomach and the food propulsion rate in small intestine were detected in20min,1h and2h individually.Results:1. After incubation with Curcumin, the spontaneous contractile amplitude of duodenal smooth muscle of mice was decreased significantly (P<0.01). The decreased contractile amplitude of duodenal smooth muscle was associated with the increased concentration of Curcumin in a dose dependent fashion.2. ACh induced the obvious contraction of duodenum, then the contractile amplitude of duodenum was significantly decreased by Curcumin (P<0.01).3. Atropine or epinephrine induced obvious relaxation of duodenum, the decreased contractile amplitude of duodenum was fall further by Curcumin (P<0.01).4. By introgastric administration of Curcumin (200mg/kg) to mice, the food residual rate in stomach and the food propulsion rate in small intestine had no obvious changes in20min,1h and2h(P>0.05).Conclusions:1. Curcumin has a direct vasodilator effect on isolated duodenal smooth muscle in a dose dependent fashion.2. During either contraction with ACh or relaxation with atropine and epinephrine, Curcumin can diastole the isolated duodenal smooth muscle of mice.3. There has no direct effects on the peristalsis of gastrointestine of mice after Curcumin (200mg/kg) administered by lavage.