**2.2 Histological study**

The liver and Kidney tissues were dehydrated in an ascending grade of alcohol (ethanol), cleared in xylene and embedded in paraffin wax. Serial sections of 7 microns thick were obtained using a rotatory microtome. The deparaffinised sections were stained routinely with hematoxylin and eosin reagent. Photomicrographs of the specimens were obtained using digital research photographic microscope in the University of Benin research laboratory.

### **2.3 Liver enzyme assay and other metabolic panel**

Blood samples were collected from all the rats within different treatment groups through the orbital venous plexuses on the last day of the experiment under chloroform anaesthesia. Blood serum was separated by centrifugation at 3000 rpm for 15 min. Serum was analysed colorimetrically for total protein, albumin, transaminases (aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Blood samples were also collected and analyzed for blood urea nitrogen (BUN) and serum creatinine (Scr) by using the commercial kits (McClatchey, 1994)

#### **2.4 Approval**

This study was given consent and approval for the methodology and other ethical issues concerning the work by the University of Benin Research Ethics Ccommittee.

#### **2.5 Statistical analysis**

The results were expressed as mean ±SD. Data obtained from liver function test, blood urea nitrogen (BUN) and serum creatinine (Scr) were subjected to statistical analysis using one way analysis of variance (ANOVA) then followed with post hoc test (Least Square Deviation), P value of less than 0.05 was considered significant.

The Effects of Sildenafil Citrate on the Liver

cell (Mag. X400).

(Mag. X400).

**3.2 Kidney tissue** 

the control (Figure 6)

and Kidneys of Adult Wistar Rats (*Rattus norvegicus*) – A Histological Study 121

Fig. 3. Photomicrograph of the liver showing in the treatment groups 'B' that received 0.70mg/kg body weight of Sildenafil citrate. There were atrophic and degenerative changes around the hepatocytes and central vein, which was dilated and contained lysed red blood

Fig. 4. Photomicrograph of the liver showing in the treatment groups 'C' that received 1.43mg/kg body weight of Sildenafil citrate. There were marked atrophic and degenerative changes around the hepatocytes and lysed red blood cell containing dilated central vein

The control sections of the kidneys showed normal histological features. The section indicated a detailed cortical parenchyma and the renal corpuscles appeared as dense rounded structures

The kidneys of the animals in group 'A' treated with 0.25mg/kg of Sildenafil citrate revealed some level of cyto-architectural distortion of the cortical structures as compared to

with the glomerulus surrounded by a narrow Bowman's spaces (Figure 5)
