RESUMO
Objective To establish a rat model of persistent intestinal mucosal injury.Methods The rat model of persistent intestinal mucosal injury was induced by intraperitoneal injection of methotrexate.The food intake and body weight of all the rats were recorded.Pathological changes were observed using HE staining, the level of D-lactate and diam-ine oxidase in plasma, and myeloperoxidase and malondiadehyde in the intestinal tissue were measured by biochemistry. Results After modeling, the rat body weight and food intake were decreased.On day 4, the scores of mucosal damage, the levels of plasma D-lactate, DAO, MPO and MDA were significantly increased (P<0.05).On day 5, the intestinal damages of rats began to restore, and there was no significant difference among groups on day 6.The symptoms after the secondary injection were similar to those after the first injection, and the rats recovered gradually at day 12.Conclusions Intestinal mucosal injury in rats induced by 20 mg/kg MTX is an acute injury process, the course only lasts for 4-5 days. Intermittent injections twice of 10 mg/kg MTX can cause persistent intestinal mucosal injury in rats.This persistent injury model is more suitable for nutritional therapy evaluation in medium-and long-term studies of nutritional therapy.
RESUMO
Objective To evaluate the effects of peptide-based enteral nutrition (PBEN) on inflammatory response and immune function in rats with intestinal mucositis.Methods 48 Sprague-Dawley male rats were randomly divided into 6 groups (all n =8):basal feed group (BFG),PBEN group (PBENG),intact protein enteral nutrition group (IPENG),methotrexate (MTX) + BFG,MTX + PBENG,and MTX + IPENG.The rats in MTX + BFG,MTX + PENG,and MTX + IPENG were intraperitoneal injected with MTX 10 mg/kg on day 0 and day 6 to induce sustained intestinal injury.From day 1,BFG and MTX + BFG were fed with basal feed,PBENG and MTX + PBENG with PBEN,IPENG and MTX + IPENG with IPEN.The daily energy intake of each rat was 1.80 kJ/g body weight.All the rats were sacrificed on day 11.The pathological changes of intestinal tissue were observed with HE staining,the levels of tissue myeloperoxidase (MPO),nitric oxide (NO),inducible nitric oxide synthase (iNOS),the thymus index and spleen gland index of intestinal tissue were measured using colorimetry,and the serum levels of immunoglobulins IgG,IgA,and IgM were determined with enzyme-linked immunosorbent assay.Results There were no significant differences among BFG,PBENG,and IPENG in each index.Serious injury of intestinal mucosa was observed in MTX groups.Significant differences were noted in all indexes between MTX + BFG and BFG (all P ＜0.05).The mucosal damage score (Chiu score) and the level of MPO and iNOS in MTX + PBENG were significantly lower than those in MTX + BFG [2.3 ± 0.69vs.2.96 ± 0.75,P =0.003 ; (2.30 ± 0.42) U/g tissue vs.(2.98 ± 0.23) U/g tissue,P =0.040 ; (0.37 ±0.06) U/mg prot vs.(0.44 ±0.10) U/rag prot,P =0.030] ; the serum levels of IgG and IgA were significantly higher than those in MTX + BFG (P =0.015,P =0.021) ; however,the levels of NO and IgM were not significantly different between the 2 groups (P =0.597,P =0.160).There were no statistically significant differences between MTX + IPENG and MTX + BFG in terms of the indexes (all P ＞ 0.05).Conclusion PBEN can reduce the inflammation response and improve the immune function in intestinal mucositis rat.
