Effect of sildenafil citrate on secondary healing in full thickness skin defects in experiment

Exploring the Multifaceted Potential of Sildenafil in Medicine

Phosphodiesterase type 5 (PDE5) is pivotal in cellular signalling, regulating cyclic guanosine monophosphate (cGMP) levels crucial for smooth muscle relaxation and vasodilation. By targeting cGMP for degradation, PDE5 inhibits sustained vasodilation. PDE5 operates in diverse anatomical regions, with its upregulation linked to various pathologies, including cancer and neurodegenerative diseases. Sildenafil, a selective PDE5 inhibitor, is prescribed for erectile dysfunction and pulmonary arterial hypertension. However, considering the extensive roles of PDE5, sildenafil might be useful in other pathologies. This review aims to comprehensively explore sildenafil's therapeutic potential across medicine, addressing a gap in the current literature. Recognising sildenafil's broader potential may unveil new treatment avenues, optimising existing approaches and broadening its clinical application.

Sildenafil Counteracts the In Vitro Activation of CXCL-9, CXCL-10 and CXCL-11/CXCR3 Axis Induced by Reactive Oxygen Species in Scleroderma Fibroblasts

Oxidative stress plays a key role in systemic sclerosis (SSc) pathogenesis, and an altered redox homeostasis might be responsible for abnormal inflammatory status, fibrosis and tissue damage extension. In this study, we explored the effect of the phosphodiesterase type 5 inhibitor sildenafil in modulating the activation of the CXCL-9, -10, -11/CXCR3 axis, which is fundamental in the perpetuation of inflammation in different autoimmune diseases, in the cell culture of SSc human dermal fibroblasts exposed to a pro-oxidant environment. We observed that sildenafil significantly reduced gene expression and release of CXCL-9, -10 and -11, inhibited the CXCR3 action and suppressed the activation of STAT1-, JNK- and p38MAPK pathways. This in vitro study on dermal fibroblasts supports clinical studies to consider the efficacy of sildenafil in preventing tissue damage and fibrosis in SSc by targeting central biomarkers of disease progression, vascular injuries and fibrosis and reducing the pro-inflammatory activation induced by oxidative stress.

Impact of sildenafil-containing ointment on wound healing in healthy and experimental diabetic rats

AIM

The study evaluated the effect of different concentrations of sildenafil-containing ointment on wound healing in healthy and streptozotocin (STZ)-induced diabetic rats.

METHODS

A total of 108 Sprague Dawley male rats aged 5 months were randomly divided into two groups: healthy and diabetes-inducing rats. Following induction of diabetes by intraperitoneal STZ injection (55 mg/kg), diabetic and healthy rats were subdivided into six groups (9 rats each). Linear incisions of the dorsal backs of rats were made. Then, rats were treated twice daily with either 2%, 2% + Fucidin, 5% sildenafil-containing ointments, oral sildenafil (13.0 mg/kg), moist exposed burn ointment or vehicle. During treatment, the percent reduction of the wound area and tensile strength were measured on days 3, 7 and 10. Furthermore, histopathology was performed on the wounded skin on similar days for the assessment of collagen synthesis and proliferation of new capillary vessels.

RESULTS

In healthy and STZ-induced diabetic rats, the percent reduction in wound area on day 3 was significantly higher in sildenafil-containing ointment-treated groups than all other groups, whereas on day 7 only the 5% sildenafil-containing ointment-treated group showed better response in healthy rats. Although the sildenafil-containing ointment significantly showed better tensile strength than all other groups, the 5% sildenafil-treated group significantly enhanced the tensile better than the 2% and 2% + Fucidin dose. Furthermore, the histological evaluation revealed that sildenafil-containing ointment promoted collagen synthesis and proliferation of new capillary vessels.

CONCLUSION

Our results suggest that sildenafil-containing ointment can provide an advantage in wound healing by promoting wound contractions and resistance to wound breakage in healthy and diabetic conditions. Therefore, 5% sildenafil-containing ointment can be used as a support factor for wound healing in healthy and diabetic conditions; however, clinical trials are required to confirm the benefits of sildenafil in wound healing.