Effects of chronic restraint stress and 17-β-estradiol replacement on oxidative stress in the spinal cord of ovariectomized female rats

Dynamic oxidative stress and DNA damage induced by oestrogen deficiency and protective effects of puerarin and 17β-oestradiol in ovariectomized rats

Oxidative stress plays an essential role in the pathogenesis of cardiovascular diseases and osteoporosis resulting from oestrogen deficiency in the postmenopausal period. In this report, we observed a dynamic change of oxidative stress and DNA damage after ovariectomy in female rats. We then compared phytoestrogen puerarin and 17β-oestradiol (E₂) in their effects on oestrogen deficiency-induced oxidative stress and DNA damage. Serum total antioxidant capacity (TAC), malondialdehyde (MDA) and lymphocytes DNA damage (comet%) were measured. There was a gradual increase in oxidative stress in the ovariectomized (OVX) rats over time after ovariectomy, as compared to rats receiving sham operation. OVX rats that were on puerarin and E₂ showed increased TAC and decreased MDA in the serum, as well as decreased lymphocytes comet%. Puerarin appeared to have a more powerful protective effect on DNA oxidative damage than E₂. The study indicates that postmenopausal women may benefit from phytoestrogen puerarin.

Gonadal hormones and oxidative stress interaction differentially affects survival of male and female mice after lung Klebsiella pneumoniae infection

Survival of mice after Klebsiella pneumoniae infection and phagocytosis by alveolar macrophages (AMs), in the presence or absence of ozone (O(3)) exposure prior to infection, is sex dependent. The objective of this work was to study the role of gonadal hormones, 5α-dihydrotestosterone (DHT) and 17β-estradiol (E(2)), on mouse survival after filtered air (FA) or O(3) exposure. Gonadectomized female (G×F) and male (G×M) mice implanted with control or hormone pellets (DHT in G×F, or E(2) in G×M), exposed to O(3) (2 ppm, 3h) or FA, and infected with K. pneumoniae were monitored for survival. Survival in G×F was identical after FA or O(3) exposure; in G×M O(3) exposure resulted in lower survival compared to FA. In O(3)-exposed females, gonadectomy resulted in increased survival compared to intact females or to G×M+E(2). A similar effect was observed in G×F+DHT. The combined negative effect of oxidative stress and hormone on survival was higher for E(2). Gonadectomy eliminated (females) or minimized (males) the previously observed sex differences in survival in response to oxidative stress, and hormone treatment restored them. These findings indicate that gonadal hormones and/or oxidative stress have a significant effect on mouse survival.