الفهرس 
Inflammatory Bowel DiseaseOnly 14 pages are availabe for public view
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Abstract
The present study has been conducted to evaluate the protective role of sildenafil citrate against acetic acid-induced colitis, both acute and chronic.
The animals were divided into 8 groups as the following:
* Group 1 (Normal control group): received the vehicle only.
* Group 2 (5 mg Sildenafil-treated control): received sildenafil at dose 5 mg/kg body weight, dissolved in tap water.
* Group 3 (10 mg Sildenafil-treated control): received sildenafil at dose 10 mg/kg body weight, dissolved in tap water.
* Group 4 (acute colitis): received intrarectal 5% acetic acid at dose 1 ml.
* Group 5 (Sildenafil-treated acute colitis): received sildenafil at dose 5 mg/kg body weight, starting 5 minutes after intrarectal administration of acetic acid and continued for 3 days.
* Group 6 (chronic colitis): received intrarectal 5% acetic acid at dose 1 ml and a second dose after 16 days.
* Group 7 (Sildenafil-treated chronic colitis): received sildenafil at dose 5 mg/kg body weight, starting 5 minutes after intrarectal administration of the second dose of acetic acid and continued for 3 days.
* Group 8 (Sildenafil-treated chronic colitis): received sildenafil at of 10 mg/kg body weight, starting 5 minutes after intrarectal administration of the second dose of acetic acid and continued for 3 days.
The results of biochemical, histopathological, oxidative stress and antioxidant defense system markers revealed that acetic acid induced an inflammatory ulcerative colitis indicated by elevated serum TNF-α and IL-1β. The antioxidant defense system parameters in both colon and rectum tissues (GSH, SOD and Px) are decreased as a result of acetic acid administration. On the other hand, the oxidative stress parameter MDA level which is a lipid peroxidation index was markedly increased in acetic acid-administered rats. These results are associated with the histopathological alterations in the colon tissue including inflammatory cells infiltration, hemorrhage, cytomegally, oedema, ulceration and hyperemia.
In addition, serum liver function parameters including; AST, ALT and total bilirubin were significantly in both acute and chronic colitis groups. On the other hand, serum albumin concentration was non-significantly affected. Similarly, renal function parameters such as urea and creatinine were also significantly elevated in serum of acetic acid-induced colitis in rats.
Upon treatment of rats, sildenafil significantly increased the antioxidant indices (GSH, SOD and Px) while malondialdhide (MDA) level was decreased in sildenafil treated rats. Serum TNF-α and IL-1β as well as the elevated liver and renal function parametes were also significantly decreased following treatment of rats with sildenafil citrate.
Histopathological findings come to confirm biochemical analysis since there was a marked improvement in the colon tissue as compared with both acute and chronic colitis groups. In spite of this improvement, there were still some inflammatory cells infiltration and hemorrhage.
These results showed that sildenafil citrate exerted noticeable protective effects against acetic acid-induced colitis in rats. However, further studies are necessary to assess the benefits and safety of sildenafil citrate