Increased Gut Absorptive Capacity In Rats With Severe Head Injury After Feeding With Probiotics

Objective: The absorptive capacity of the gut is decreased after severe head injury (SHI), so many patients with clinical head injury cannot tolerate early enteral nutrition because of malabsorption. Vomiting, pain and distention were common complaints; some patients even developed bowel obstruction and necrotic enteritis. H?rtl et al.reported that the amount of nutrition in the first five days was related to death; every 10-kcal/kg decrease in caloric intake was associated with a 30-40% increase in mortality rate. Therefore, restoration of gut absorptive capacity(GAC) may be useful for further reducing morbidity and mortality rates following SHI. Probiotics have been used for centuries for their health-promoting effects. To date, their recognized benefits have mainly concerned prevention of enterogenic infection and enhancement of immune defenses in clinical therapy. However, there have been few studies on the effect of probiotics on absorptive function after SHI. Therefore, we conducted this experimental study to determine whether probiotics improve gut absorptive function after SHI, thus providing evidence to support nutritional regimens in the clinic.Methods: A rat model in which SHI was induced by air percussion was used. SHI rats were randomly assigned to two treatment groups: group A received the standard enteral diet TRENSINE (SANJIU Co. Ltd., Guangdong, China); group B received TRENSINE plus three viable probiotics capsules of Bifidobacterium long, Lactobacillus acidophilus and Enterococcus fecalis (Jinchen Pharmaceutical Co. Ltd., Shanxi, China). Both the A and B groups were fed enteral nutrition (125kcal/kg body weight per day) by gastric irrigation, Probiotics (700mg/kg body weight per day) were added to the enteral nutrition in group B; each strain was included at 108 colony-forming units (CFU)/g of viable lyophilized bacteria. Rats without head injury (group C, sham-operated) were maintained on standard chow diet throughout the study. The enteral diets were infused for 14 days after SHI. The blood,urine, and feces were collected for analysis on days 3, 7 and 14 after SHI. Results:1. D-xylose concentrationSHI induced a decrease in D-xylose level (A, B vs C, P<0.01) in one week, but on the fourteenth day,the serum D-xylose level in group B (but not A) had reached that in group C (B vs C, P>0.05, A vs C, P<0.05). The D-xylose concentration was lower in group A than in group B two weeks after SHI (A vs B, P<0.05 or P<0.01).2. Apparent protein digestibilityThe apparent protein digestibility in the two groups with SHI was lower than in the controls after two weeks (A, B vs C, P<0.01). However, the apparent protein digestibility in group B was higher than in group A during the study (A vs B, P<0.01).3. Plasma cholesterol levelsThe plasma cholesterol levels in both groups with SHI were lower than control values on the third day after SHI (A, B vs C, P<0.01). However, the cholesterol contents of the three groups did not differ significantly after three days (A, B vs C, P>0.05).4. Weight lossWeight loss occurred two weeks after SHI and was not corrected by probiotics. However the weight loss was less in the group fed probiotics on the fourteenth day (A vs B, P<0.01).5. Villus height and surface areaVillus height and surface area decreased (A, B vs C, P<0.01) one week after SHI; on the fourteenth day, the villus surface area in group B reached that in group C (B vs C, P>0.05, A vs C, P<0.05). However, the villus height in group C was still greater than in either of the groups with SHI (A, B vs C, P<0.05). Villus height and surface area were modified significantly by probiotics two weeks after SHI (A vs B, P<0.01 or P<0.05).6. Disaccharidase and Na+-K+-ATPase activitiesDisaccharidase and Na+-K+-ATPase activities decreased two weeks after SHI (A, B vs C, P<0.05 or P<0.01). Although the disaccharidase activity was higher in group B than A, the difference was not statistically significant (A vs B , P>0.05). The Na+-K+-ATPase level was not modified by probiotics; no difference was observed between the two groups with SHI (A vs B, P>0.05). 7.Intestinal floraThe numbers of Lactobacillus and Bacillus bifidus decreased and Escherichia counts increased two weeks after SHI (A, B vs C, P<0.05 or P<0.01). There were significantly fewer Bacillus bifidus in group A than group B at every time point (A vs B, P<0.05 or P<0.01); Escherichia coli showed the opposite trend (A vs B, P<0.01). The Lactobacillus counts were modified by probiotics on the third day (A vs B, P<0.01), but there was no difference in these counts between A and B on the seventh day after SHI (A vs B, P>0.05).The numbers of Bacteroides and Clostridium were lower than in controls two weeks after SHI (A, B vs C, P<0.05 or P<0.01). The Bacteroides count was modified by probiotics on the third day after SHI (A vs B, P<0.01), but on the seventh day after SHI,the difference in these counts between groups A and B was not significant (A vs B, P>0.05). The Enterococcus counts were higher in group B than group C during 14 days (B vs C, P<0.05 or P<0.01), but there was no significant difference between the two SHI groups (A vs B, P>0.05).8. Intestinal transit testSHI induced gut motion dysfunction, and this did not recover within two weeks (A, B vs C, P<0.05 or P<0.01). The intestinal transit rate was not modified by probiotics. On the fourteenth day, the intestinal transit rates in groups A and B were 70.53±6.20% and 71.19±7.80%, respectively; the difference was not statistically significant (A vs B, P>0.05).Conclusion:1.Gut absorptive capacity was severely depressed after SHI.Only standard enteral nutrition is provided, the intestinal mucosa cannot digest and absorb nutrients efficiently after SHI.2.Probiotics proved to be effective in improving the absorption of carbohydrate and protein, and the relevant reasons may have included increase in the villus surface area, modulation of bacterial translocation.