The Histological Effect of Aqueous Ginger Extract on Kidneys and Lungs of Diabetic Rats

Diabetes is a disorder affecting various-aged humans and which can with time cause serious problems for the patient. Medicinal plants are known for their hypoglycemic effects; and among which is ginger (Zingiber officinale) known also for its culinary uses. This study, therefore, was undertaken to evaluate the histological effect of 21-day treatment of aqueous ginger extract used at 500 mg / kg BW on female diabetic rats. Fifteen female albino rats were divided into three groups; Group I: control, Group II: non-treated diabetic, and Group III: ginger extract-treated diabetic rats. The ginger extract-treated diabetic group received the daily dose orally for three weeks. Results show that organ weight was not significantly changed. Light microscopic examination of 5μm sections of extract-treated Kidney and Lung of the diabetic rats revealed approximately normal histological structure compared with the untreated ones. The normal appearance of glomeruli and alveoli as well as the normal alveolar wall assumed the ameliorative effect ginger aqueous extract could have on kidney and lung of diabetic rats. These results indicated that this dose of ginger extract may be effective in the treatment of diabetic rats.

Many studies reported the hypoglycemic effect of different forms of ginger in both human subjects and laboratory animals.Examples included the use of aqueous extract in alloxan-induced diabetic rats (Jafri et al., 2011) and 6-gingerol or aqueous ginger extract in STZ-induced diabetic rats (Abdulrazaq et al., 2012;Sukalingam et al., 2013).
Ginger was proved more potent renoprotective agent in both acute and chronic renal failure (Mahmoud et al., 2012;Swaroopa, 2013).There are few studies concerning the effect of extracts obtained from this plant alone on lungs and kidney.Therefore, in this study, we tried to investigate and evaluate the histological effect of ginger aqueous extract (500 mg /kg BW) on these organs in laboratory diabetic-and non-diabetic-rats.

Experimental Procedures
The rhizomes of ginger were purchased from a local market in Amman.The study was approved by the Institutional Review Board of Al-Balqa Applied University.The extract was prepared from 30 g powder of cleaned dried grinded plant refluxed at room temperature with 100 ml of hot water at 150 rpm for two weeks.Further steps were done to get extract with a concentraion of 1g/ml taking in consideration the starting weight of the plant.The method illustrated by Elshater et al., (2009) was used to prepare the extract.Fifteen healthy adult female albino rats were purchased from the faculty of medicine, University of Jordan.The rats were weighed and randomly divided into three groups containing five rats each: Group I: control, Group II: non-treated diabetic, and Group III: ginger extract-treated diabetic rats.The rats were fastened overnight, then alloxan induced diabetes was obtained by intraperitoneal injection of alloxan monohydrate (Sigma, St. Louis, MO, USA) dissolved in distilled water with a dose of 65 mg/kg BW (Al-logmani and Zari, 2011).After induction of diabetes, the rats in group III were treated with ginger aqueous extract orally for 21 days.The plant extract was administered as shown in Table 1.

Histopathological examination
After 21 days from the beginning of the experiment, the rats were weighed, sacrificed and dissected.Then the Lungs and kidneys were removed, cleaned, weighed and immediately small pieces of them were taken, fixed in 10% buffered formaldehyde solution and stored until performing light microscopy technique.Relative organ weights were computed as follows (Bashir et al., 2015): Relative organ weight= organ weight (g)/body weight (g) x 100.The fixed organs were examined by histopathological method.The light microscopy involves preparation of 5µm sections stained with hematoxylin and eosin stain and finally the sections were examined under compound light microscope with 400X magnification.The procedure used in light microscopy is described in earlier in literature (Al-Qudah, 2016;Al-Qudah et al., 2016).

Statistical analyses:
Data were expressed as mean ± standard deviation.The differences were considered to be significant when P value was <0.05.

Results
The relative kidney and lung weight of rats were not significantly (p>0.05)different from those of control at the examined extract dose (Table 2).The histopathological examination illustrated the ameliorative effect of ginger aqueous extract on kidney of diabetic rats compared with the control (Figure 1). Figure 1a shows the normal architecture of kidney in control rats; normal glomerulus as well as normal proximal and distal tubules.In contrast Figure 1b demonstrates the abnormal histopathological changes in the kidney tissue of diabetic rats including abnormal glomerulus, congestion and necrosis of proximal and distal tubules of the nephron.These histopathological changes were approximately normalized when the diabetic rats were treated with the extract compared with the control (Figure 1c).The glomerulus was found approximately normal as was the proximal and distal tubules.

Table 1 .
Experimental design: Oral administrations of ginger aqueous extract to different groups of adult female albino rats