Abstract

Background: Diabetes mellitus is an unpredictable issue that is portrayed by hyperglycemia coming about because of breakdown in insulin discharge and activity. As of late curcumin extract have been reported to be useful in treatment of type II diabetes. Aim of the work: In this research curcumin extract was used instead of chemical drugs for the treatment of diabetes mellitus. Material and methods: 30 male adult albino rats aged 5-7 months and their average weight was 150-200 grams were divided into three groups. The first one (n=10) control group, the second group (n=10) was injected with a single dose of alloxan (42 mg/kg). The third group (n=10) was injected with alloxan and after 3 days was received curcumin extract orally 80mg/kgm daily for one month. The rats were scarified after the last dose of the drug and their pancreases were removed, fixed and different sections were prepared and stained for light microscope study. Results: After induction of diabetes the islets of Langerhans revealed architectural disarray. The islets cells showed atrophy in size with cellular necrobiosis associated with cystic dilatation and luminal eosinophilic casts. The intensity anti-insulin antibody reaction was decreased. So donation of curcumin extract reduced the islets cells damage and increase in the intensity of anti-insulin antibody reaction. Conclusion: The present study revealed that curcumin extract has potential effect in treatment of type II diabetes.

1. Introduction

The pancreas is particularly an important organ from the medical point of view because it is commonly subjected to two important diseases: diabetes mellitus and pancreatic cancer ¹. The diabetes is a problem of morbidity and it is one of the five leading causes of death in the world ². Several investigations in human and animal models have demonstrated changes in the cell antioxidant status in diabetes.

The unsettling influences in the defense system in different tissues from animal models were accounted for. There was evidence that elevation in glucose concentration may depress natural antioxidants defense agents such as vitamin C and glutathione ³. On the other hand, oxidative stress causes type I diabetes especially through apoptosis of pancreatic B-cells and insulin resistance in type Π diabetes ^{4, 5, 6}.

Alloxan causes diabetes in animals through its ability to destroy the insulin-producing B-cells of the pancreas ⁷. Recently, overproduction of reactive oxygen and nitrogen species, lowered antioxidant defense in humans were associated with diabetes mellitus. Also the antioxidants help in neutralization of the effects of free radicals formed when body cells burn oxygen ⁸.

The employ of medicinal plants or their active ingredients has become a progressively more used for treatment of various pancreatic disorders including diabetes mellitus. One of these medicinal plants is Curcumin (Diferuloyl methane), a polyphenol derived from the herbal remedy and dietary spice turmeric, ^{9, 10}. It had a long history of restorative uses in India and Southeast Asia was known to display an assortment of pharmacological impacts including calming, hostile to tumor, against HIV (Human Immunodeficiency Virus) and anti-infectious activities following oral or topical administration, ¹¹. Curcumin was a strong antioxidant capacity at neutral and acidic pH.It could inhibit different cell signaling pathways i.e. its effect on cellular enzyme such as cyclooxygenase and glutathione S- transfereses, immune-modulation and effect on angiogenesis and cell-cell adhesion ¹².

The use of curcumin extract for treatment of diabetes mellitus still needs further investigation in order to validate its clinical application as remedy for pancreatic β cells damage.

2. Material and Methods

In this work 30 male adult albino rats aged 5-7 months and their average weight was I50-200 grams will be using. They divided into three groups.

Group I: Control and consisted of ten rats (-ve control).

Group II: Experimental and consisted of ten rats and was subjected to the induction of diabetes by receiving intravenous alloxan at a dose of 42 mg/kg of body weight into tail veins(Sigma Co, USA) dissolved in distilled water ¹³. Serum glucose levels was checked after 72 hour and the rats with serum glucose level ≥ 200mg/dl or over was considered diabetic and were used for this study ¹⁴.

Group III: Experimental and consists of ten rats and were injected with alloxan and after 3 days were received curcumin extract orally 80mg/kgm by gastric tube daily for one month ¹⁵.

At the end of the experiment, the fasted rats were sacrificed by decapitation and their pancreatic glands were rapidly excised, rinsed in saline and fixed in I0% formol saline. Their blood samples were collected to determine the blood glucose level.

Specimens from pancreas of each group were removed at the end of experiment and after fixation in I0% formol saline for 24 hours. The tissues were processed according ¹⁶.

For immunohis to chemistry study the paraffin pancreatic sections were de-waxed in xylene and then rehydrated. The slides were prepared according ¹⁷.

3. Results

Ÿ Histological results:

Group I:

The islets of Langerhans appeared to be ellipsoid or spherical structures of varying sizes and were unevenly scattered between the pancreatic acini. Each islet was consisted of epithelial cells which form trabecular structures separated by a dense network of anastomosing capillaries. The epithelial cells were round or oval in shape with central rounded nuclei, surrounded with a delicate cellular membrane, filled with a fine granular cytoplasm and form tube like structures around central capillary (Figure 2, Figure 3).

Group II:

The islets of Langerhans revealed significant architectural disarray. They were damaged and shrunken in size. The islets cells showed atrophy in size with cellular necrobiosis associated with cystic dilatation with luminal eosinophilic casts in the duct system (Figure 4, Figure 5).

Group III: The islets of Langerhans appeared to restore their size and shape with normal intact cells without ductal cystic dilatation in duct system compared with group II (Figure 6, Figure 7).

Ÿ Immunohistochemical results:

Group I:

The islets of Langerhans of group I showed sever reaction in almost all of the islet cells (Figure 8) and Table 1.

Group II:

The islets of Langerhans of group I showed no reaction in almost all of the islet cells (Figure 9) and Table 1.

Group III:

The islets of Langerhans of group I showed sever reaction in almost all of the islet cells (Figure 10) and Table 1.

Ÿ Morphometric results: Morphometric study showed:

Ÿ Blood glucose results:

Group I: The average value of fasting blood glucose levels was I00.6mg/dl (Figure 1).

Group II: The average value of fasting blood glucose levels was found to be increased to (297.8mg/dl) compared with group I (Figure 1).

Group III: The average value of fasting blood glucose levels was found to be decreased to (I07.II mg/dl) compared with the group II (Figure 1).

4. Discussion

Diabetes mellitus is the most common endocrine disease accompanied with various metabolic disorders ¹⁸. It leads to hyperglycemia, hyperlipidemia, hypertension, atherosclerosis, retinopathy, neuropathy and nephropathy ^{2, 19}. Alloxan is well known for its selective pancreatic islets cells toxicity and has been extensively used in induced diabetes mellitus in animals. It causes diabetes in animals through its ability to destroy the insulin-producing B-cells of the pancreas ^{20, 21}. Also it increases the free radicals production and causes pancreatic tissues injury with consequent increase in lipid peroxidation which contributes to the increased rate of hepatic glucose production. The alloxan is taken up by the B-cells via the glucose transporter GLUTZ and causes alkylation of DNA and reduction of ATP and NAD content ^{7, 22}.

The results of the present study revealed that induction of diabetes by alloxan resulted in abnormal histological changes in islets of Langerhans and their cells. They were damaged and shrunken.The islets cells showed atrophy in size with cellular necrobiosis associated with cystic dilatation with luminal eosinophilic casts in the duct system.These findings are in agreement with those described by ^{7, 8, 23, 24}. They stated that the alloxan oxidizes the pancreatic B-cell glucokinase with concomitant inactivation of the enzyme which couples changes in the serum glucose level that inhibit glucose induced insulin secretion and lead to necrosis of the pancreatic B-cells.

In the present study a significant decrease in insulin contents in diabetic rats was observed. These findings came in accordance with ²⁵ who suggested that one of the causes of diabetes was the impaired insulin response to glucose. ²⁶ Saied that the insulin receptor in pancreatic B-cells created an insulin secretory defect associated with a modest decrease of islet size. ²⁷ Proved that the loss of insulin production was demonstrated as loss of insulin-staining cells of the islets of alloxan treated mice.

In the present work, curcumin extract administration reduced markedly the degree of damage produced in the pancreatic islets as a result of induction of diabetes. Curcumin increased islet viability and delayed islet reactive oxygen species (ROS) production, which was mediated through inhibiting poly ADP-ribose polymerase-I activation ²⁸.

Curcumin extract administration to diabetic rats showed improvement in the pancreatic islets cells structure, increase in the number of B-cells as well as increase in islets area compared to diabetic animals. Also significant increase in insulin hormone contents was observed. These findings are in agreement with ^{29, 30, 31, 32} whereas curcumin and its analogues treatments increased the number of small pancreatic islets and decreased lymphocyte infiltration in pancreatic islets and they played antioxidant defense. Thus curcumin as a natural polyphenolic source exerts its beneficial effects by modulating different signaling molecules including transcription factors, chemokines, cytokines, tumor suppressor genes, adhesion molecules, microRNAs.

5. Conclusion

The present study revealed that curcumin extract administrations are effective in protecting the islets of Langerhans against diabetes and considered to be effective in treatment of diabetes.

References