The effects of vitamin B12 on the TLR-4/NF-κB signaling pathway in ovarian ischemia-reperfusion injury-related inflammation

Abstract

Ovarian ischemia is a gynecological emergency case that occurs as a result of ovarian torsion. Oxidative stress and inflammation play central roles in the development of ischemia/reperfusion injuries. We investigated the effects of Vitamin B12, thought to possess antioxidant characteristics on oxidative stress and the toll-like receptor 4 (TLR-4)/nuclear factor kappa B (NF-κB) signaling pathway in the ovaries during ischemia-reperfusion. Forty-eight rats were randomly assigned into six groups and the groups are designed as follows: Control (C), Ischemia (I), Ischemia + Vitamin B12 (I + B12), Ischemia-Reperfusion (I/R), I/R + Vitamin B12 (I/R + B12) and Sham + Vitamin B12. Vitamin B12 was administered at a dose of 400 mcg/kg via the i.p. route once daily for three days before I/R procedure. Tissue interleukin-1β (IL-1β) and interleukin-6 (IL-6) and malondialdehyde (MDA) levels in ovarian tissue increased following I/R, while glutathione (GSH) levels decreased. Moreover, extensive congestion, edema, hemorrhage and defective follicle were observed. Both NF-κB and TLR-4 expression levels also increased in the group exposed to I/R. While GSH levels increased, IL-1β, IL-6, MDA, NF-κB and TLR-4 levels decreased with Vitamin B12 treatment. In addition, ovarian tissue without edema, mild congestion, and normal-appearing follicles were observed following Vitamin B12 administration. The findings showed that I/R in ovarian tissue resulted in significant tissue damage by increasing oxidative stress and inflammation. However, Vitamin B12 application was effective and alternative agent in reducing injury deriving from inflammation and oxidative stress developing in association with I/R in ovarian tissue.