Feasibility Of L-Arg Salt Solution For Gastrointestinal Disorder Model In Rats: Based On The RAS System And NO/cGMP Path Ways

Objective: We aimed to evaluate the feasibility of L-Arg salt solution for gastrointestinal disorder model in rats based on the RAS system and NO/c GMP pathways.Methods: 93 clean SD rats were used in the experiment, of which 15 were used in pre-experiment, and others were randomly divided into 5 groups using the random number table. Rats in group A and B were respectively treated with L-Arg salt solution or with normal saline alone for 5 days(n=18), group C was treated with L-Arg salt solution and group D was treated with normal saline for 10 days(n=18). Group E was the normal control group, rats in which were treated with nothing(n=6). Samples were collected and the outcomes were tested at day 1st, day 7th, and day 14 th after different treatments in experimental groups. We finished these works for rats in group E at day 14 th.Results: 1. Compared with normal saline groups, the body weight of rats was more significantly decreased in L-Arg groups, and it also more slowly increased after interventions. The body weight of rats in normal saline groups was slightly changed when compared with the normal control group. 2. The small intestine anatomical structure of rats was not significantly changed in all of the experimental groups compared with the normal control group. 3. The small intestinal propulsion rate in all of experimental groups was decreased in different extent, and the change in group A was the most obvious. 4. The plasma motilin level was the most significantly decreased in group A compared with other experimental groups. There were significantly statistical significance between group A and group E in all of time points(p<0.05). The VIP level was significantly increased in group A, group B and group C, there were significantly statistical significances when compared with group E(p<0.05). 5. The renin level was significantly increased in group A, group B and group C, there were statistical significances compared with group E, and the change in group A held longer time than others. The levels of Ang II, ACE and ACE2 were not significantly changed in these experimental groups. The AT2 R level was significantly decreased in group A and group B; the change in group A was more obvious than group C(p<0.05). 6. The levels of NO and c GMP in group A were more significantly increased in group A, there were statistical significances compared with group E at different time points(p<0.05). The level of NO in group C was same with group A, but the level of c GMP was significantly decreased on the contrary. The change of NO and c GMP levels in normal saline groups were not as obvious as L-Arg groups.Conclusion: 1. Intraperitoneal injection of L- Arg salt solution can significantly decreased the gastrointestinal motility in rats, it was an ideal method for the animal model. The best strategy for this model was the 5-day intervention. 2. All of L-Arg and normal saline played an important role for this model, and changes of RAS system and NO/c GMP were the keys and the main mechanisms. 3. RAS system may play an important role for the gastrointestinal motility, it was worth researching in future.