The effect of crude aqueous and alcohol extracts of Aloe vera on the gastrointestinal tract and accessory organs of suckling rats.

[摘要] For centuries Aloe vera has been exploited for several verified and unverified medicinaluses such as wound healing, treatment of gastrointestinal ulcers and for its manybiological effects including anti-microbial, laxative, anti-inflammatory and immunostimulatoryactivities. Studies have generally focused on its effects in vitro and in adults.When nursing mothers use Aloe vera extracts, their suckling infants are at risk of indirectexposure to Aloe vera via breast feeding or directly as dietary/health supplements. Thegastrointestinal tract (GIT) of the neonate is sensitive to dietary manipulations during thesuckling period with long lasting effects that can be irreversible. Thus babies may be atrisk if administered Aloe vera extracts directly as dietary supplements or indirectly viabreast milk.The main objectives of this study were to evaluate the effects of orally administeredaqueous and alcohol extracts of Aloe vera on growth performance, the morphometry andmorphology of the gastrointestinal tract and accessory organs, and liver function ofsuckling rats. Suckling Sprague-Dawley rats (77), males (n=38) and females (n=39) of 6days old were randomly assigned to one of five treatment groups and given once daily byoral gavage a suspension of lyophilized crude alcohol or aqueous extracts of Aloe verasuspended in distilled water. Group I (control) was gavaged with distilled water (vehicle).Group II received a low dose of the aqueous extract (AqL) at 50mg. kg-1; Group IIIreceived a high dose of the aqueous extract (AqH) at 500mg. kg-1; Group IV received alow dose of the alcohol extract (AlcL) at 50mg. kg-1 whilst Group V received a high doseof the alcohol extract (AlcH) at 500mg. kg-1. The extracts and distilled water were2administered at a volume of 10ml.kg-1. The pups remained with their dams for theduration of the study and after 8 days on the treatments, the pups were humanely killed toharvest their tissues for measurements and physiological analysis. All data wereexpressed as mean ± SD and analyzed by one way ANOVA, the values were consideredstatistically significant when p < 0.05 and then a Bonferroni Post hoc test was applied.The suckling rats fed respectively with high doses of AlcH and AqH had a significantlyhigher body mass gain than the other groups (p < 0.05, one way ANOVA). Linear growthas measured by tibial length was significantly increased in the AqH group compared tothe other groups. There was no significant difference in the mass and relative density ofthe tibia bones of the rats from the different treatment groups. The differences in growthcould not be attributed to circulating concentrations of the somatotrophic hormone,Insulin-like growth factor-1 (IGF-1) which was not significantly different between thegroups.The treatments did not result in any significant differences in lengths, and mass of thesmall and large intestine, however the caecum was significantly enlarged (hypertrophy ofmuscularis, submucosa and mucosa) in the rats that received the Aloe vera extracts.Although, there was no significant difference in the mass of the rats’ livers, the lipid andglycogen content were significantly higher (p < 0.001) for the AqH group compared tothe other groups. Histologically, the hepatocytes showed enlarged nuclei, granularcytoplasm and dilated sinusoids for AqH and AlcH as compared to the control group. Anindirect assessment of liver function by measurement of blood concentrations of alkalinephosphatase (ALP) and alanine amino transaminase (ALT) did not reveal a significant difference between the groups. The non fasting concentration of metabolic substrates(glucose and triglycerides) was also not significantly different between the groups.The pups given high doses of the extracts had a significantly greater (p < 0.05) thymusmass (hyperplastic) than the other groups.The short term administration of Aloe vera extracts has shown a growth promoting effect,enhanced hepatic storage of metabolic substrates and hypertrophy of the caecum andthymus of neonatal rats. These effects need to be explored further to enhance animalproduction and health.

[发布机构] University of the Witwatersrand