The effect of aqueous ethanolic extract of Stachytarpheta cayennensis on the histology of the liver and fasting blood sugar of non-diabetic and diabetic wistar rats
C Eliakim-Ikechukwu, A Obri, A Igiri
Keywords
hypoglycaemia, liver, stachytarpheta cayennensis, wistar rat
Citation
C Eliakim-Ikechukwu, A Obri, A Igiri. The effect of aqueous ethanolic extract of Stachytarpheta cayennensis on the histology of the liver and fasting blood sugar of non-diabetic and diabetic wistar rats. The Internet Journal of Nutrition and Wellness. 2009 Volume 10 Number 1.
Abstract
Thirty-two presumably healthy rats of both sexes weighing between 160g and 200g were used in this study. The rats were randomly distributed into four groups viz A, B, C and D each having eight rats. Type 1 Diabetes mellitus was induced in groups B and D by a single intraperitoneal dose of 65mg/kgbw of streptozotocin. Group A served as the normal control while Group B served as the diabetic control and both received daily oral doses of 0.4ml of normal saline. Groups B and D received daily oral doses of 250mg/kgb.w of
Introduction
Diabetic complications are minimized by controlling the chronic hyperglycaemia. It is because of this that management of diabetes focuses on bringing down blood glucose levels thereby abolishing glucose toxicity.
The liver plays a central role in metabolism in the body including carbohydrate metabolism (Levinthal and Tavill, 1999). Levinthal and Tavill (1999) recorded a study demonstrating that a total hepatectomy in a dog results within a few hours from hypoglycaemic shock underscoring the important role the liver plays in maintaining normoglycaemia. In the presence of hepatic disease, the metabolic homeostasis of glucose is impaired (Picardi et al., 2006). This study also seeks to elicit any possible adverse effect on the histology of the liver that may hinder the regulatory mechanisms of the liver.
Materials and Methods
Plant material
Matured leaves of
Analysis of aqueous ethanolic extract of leaves
Freshly prepared extract was used to quantitatively analyse the bioactive constituents following standard methods described by Harbone (1993) and Trease and Evans (1983)
Animals
Thirty-two presumably healthy wistar rats of both sexes weighing between 160g and 200g were used in this study after approval by the Ethics Committee of the University of Calabar, Calabar-Nigeria. The animals were housed in well-ventilated cages in the animal house of the Department of Anatomy, University of Calabar, Calabar-Nigeria. They were fed with normal rat chow and given water freely using plastic containers with well fitted stainless steel nozzles. After a period of two weeks for acclimatization, they were randomly distributed into four groups A, B, C and D of eight rats each.
Induction of experimental diabetes
Streptozotocin (STZ) (Sigma Chemical Co., St. Louis, MO, USA) was reconstituted in normal saline (Atangwho et al., 2010). After an overnight fast, a single intraperitoneal injection of 65mg/kg body weight of STZ was given to twenty rats. After 72 hours of induction of diabetes fasting blood glucose was measured using One Touch Ultra Mini Glucometer (Lifescan Inc., USA) and only rats with blood glucose levels 12.7mmol/l (230mg/dl) and above were considered to be diabetic (Cetto et al., 2000). From the diabetic rats, eight rats each were randomly assigned to groups B and D
Experimental design
Group A: Normal control was given 0.4ml of normal saline solution once daily.
Group B: Diabetic control was given 0.4ml of normal saline solution once daily.
Group C: Non-diabetic, received 250mg/kgbw (0.4ml) of
Group D: Diabetic received 250mg/kgbw (0.4ml) of
Experiment lasted for 21 days; thereafter the wistar rats after an overnight fast were anaesthetized using chloroform inhalation. The peritoneum was stripped open and the liver dissected out.
Histopathological evaluation
Tissue samples from the liver were fixed in 10% buffered neutral formalin, dehydrated in ascending grades of alcohol, cleared with xylene and embedded in paraffin wax. Thin paraffin sections at 5µm were stained using haematoxylin-eosin staining technique (Luna,1968)
Statistics
Significance of differences was established using the unpaired Student’s t-test. Values at p<0.05 were considered significant
Results
Physical observation
Proptosis was observed in the second week of study in groups C and D that received plant extract. Passage of loose stools and increased urination were observed from the first week of study. Apparent general malaise and high mortality of over 50% especially in the third week of study was observed in all the groups except the normal control (Group A). The study had to be shortened to 21 days because of this Cervical lymphadenopathy and epistaxis were observed in some rats in groups ( C and D) that received
Effect of on blood glucose level.
The results of blood glucose levels in all the groups were shown in Table 1
Data represent mean ± SEM n=3 p<0.05
At the beginning of treatment, blood glucose levels in Groups B (Diabetic control) and D (diabetic, received 250mg/kgbw. of
Quantitative Phytochemical analysis, proximate and micronutrient composition of
Tables 2-5 show the percentage phytochemical and proximate composition and vitamin and mineral composition of
Data represent mean ± SEM n=3
Phytochemical analysis revealed the presence of alkaloids, flavonoids, saponins, tannins and phenols in
Data represent mean ± SEM n=3
Result revealed that
Data represent mean ± SEM n=3
Results revealed the presence of Vitamin A (4.14±0.03mg/100g), Vitamin C (56.91±1.03mg/100g), Thiamine (0.05±0.01mg/100g), Riboflavin (0.17±0.01mg/100g) and Niacin (0.41±0.02mg/100g)
Data represent mean ± SEM n=3
Results revealed the presence of Magnesium (60.00±2.40mg/100g), Calcium (90.85±2.31mg/100g), Potassium (225.47±1.18mg/100g), Sodium (11.07± 0.23mg/100g)
Phosphorus (68.03± 1.00mg/100g), Iron (0.65±0.01mg/100g), Copper (0.02±0.01mg/100g) and Selenium (0.01±0.00mg/100g)
Histopathological examination of liver
Histological examination of liver sections are shown in figures 1-4
Section reveals central vein (C), hepatocytes (H) arranged in cords radiating from the central vein. Also present are sinusoids (S).
Section reveals engorgement of the sinusoids (S), fewer hepatocytes
Figure 8
Section reveals mild sinusoidal engorgement and an apparently higher population of hepatocytes when compared with the diabetic control.
Figure 9
Section reveals a central vein, well-outlined hepatocytes and sinusoids. It resembles the section of the normal control.
Discussion
Streptozotocin which was used to induce experimental diabetes in this study acts by generation of reactive oxygen species. It also causes accumulation of thiobarbituric acid reactive substances (TBARS) which causes hepatocyte degeneration (Ohkuwa et al., 1995; Kakkar et al., 1995) so the marked distortion seen in the untreated diabetic group is expected. This will further worsen the hyperglycaemia. The liver plays a crucial role in the regulation of carbohydrate metabolism (Levinthal and Tavill, 1999) in the body and in detoxifying harmful substances. It regulates blood glucose levels by altering the glucogen stores in the liver (Guo et al., 2009) by glucogenogenesis and glyconogenesis (Holstein et al., 2002; Picardi et al ., 2006). In the presence of hepatic disease, the metabolic homeostasis of glucose is impaired (Picardi et al., 2006; Nielsen et al., 2005)
Hypoglycaemic effect seen in this study with
Present in the herb are several potent antioxidants and these include some minerals e.g. Selenium, some vitamins e.g. B vitamins, vitamin C and some phytochemicals like alkaloids and flavonoids. Flavonoids stimulate glucose uptake in peripheral tissues, regulate the activity of the rate-limiting enzymes in the carbohydrate mechanism and probably insulinomimetic (Cazarolli et al., 2008). Although each of these substances is in small proportions, it is possible that they work in concert to bring down blood glucose and restore normal hepatic functions.
Frequent passage of loose stool may be responsible for the general weakness observed.
Cases of exophthalmos seen in the treated groups may suggest an increase in intraocular pressure. The cause of this is not understood.
Epistaxis, though usually have no obvious underlying cause could result from hypertension, clotting disorder or tumors. Congestion of the liver may also be a result of increase in blood pressure. It is not clear what is responsible for these features of an increase in blood pressure but it may be possible that some of the components of the plant material may have a salt and water retaining property thereby expanding the intravascular space giving rise to increase in blood pressure.