The use of herbs and medicinal plants is a universal phenomenon. Every culture has relied on the huge variety of natural chemistry found in medicinal plants for their therapeutic properties 26. AV is a medicinal plant used traditionally in diverse therapeutic applications 27. AV supplementation can help prevent oxidative stress and might also be useful in the treatment of oxidative stress-related human disorders by virtue of its antioxidant activity 28.
The AV preventive group (group III) in the present study showed normal-appearing islet cells with cytoplasmic minimal vacuolations and pyknotic nuclei in a few islet cells and insignificant increase (P<0.05) in insulin antibody reaction and bcl2 expression compared with the control group (group I). In agreement with these findings, some researchers reported that AV was given to mice 30 days before STZ injections over a period of 73 days, after STZ injections were found to be significantly effective in inhibiting the destruction of islets of Langerhans in the pancreas 29. Previous studies have reported that in STZ diabetes oxidative stress is a confounding factor, and it contributes to the pathogenesis and complications of this disease. β-Cells are especially vulnerable to oxidative insult in that they possess a relatively poor complement of antioxidants 30. It was also suggested that the medicinal properties of AV can be investigated from the point of view of their potent antioxidant activities, absence of side effects, and economic viability 31. In addition, AV is used as a beneficial therapeutic agent that, along with other antioxidant properties, has been shown to have a protective role as a free radical scavenger in diabetic patients, as proven by its control of elevated anions in STZ-induced diabetic animal models 1. Previous studies have suggested many explanations for the antidiabetic effect of AV. The first explanation is the potent antioxidant effect of the aloe extract. Aloe has been long known to have antioxidant potential through the suppression of free radical formation and enhancement of cellular thiol status. It has also been reported to stimulate glutathione-S-transferase enzyme activity 32.
AV in group IV (curative group) in the present study failed to improve the alterations in the islet morphology (cytoplasmic vacuolations and pyknotic nuclei in many islet cells), as well as insulin antibody reaction and bcl2 expression induced by STZ. These findings were in agreement with those of a previous study 33, which reported that treatment of diabetic rats with AV extracts has no beneficial influence on the pancreas and thus may not be appropriate for the treatment of diabetes in alternative medicine. In contrast, another study has reported the potential of AV as an antidiabetic drug in AV-treated diabetic rabbits 21. Previous studies have explained these controversial results by reporting that the beneficial effect of AV is through stimulation of synthesis and release of insulin from the remnant pancreatic β cells, by studying STZ-induced diabetic rats 34,35.
The present study suggests that AV when used as a preventive agent can protect against STZ-induced diabetes in rats. Therefore, AV should be given to prediabetic patients and to individuals at high risk for diabetes.
There are no conflicts of interest.
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