Effect of low doses of progesterone in the expression of the GABA(A) receptor α4 subunit and procaspase-3 in the hypothalamus of female rats

Binge Eating Risk During Midlife and the Menopausal Transition: Sensitivity to Ovarian Hormones as Potential Mechanisms of Risk

PURPOSE OF REVIEW

Recent research suggests that binge eating may be more prevalent among women in midlife than previously believed. The menopausal transition, an important developmental stage during midlife, is characterized by substantial fluctuations and eventual decreases in ovarian hormones that may contribute to increased risk. This narrative review summarizes findings from studies of binge eating during midlife and menopause and discusses the potential role of ovarian hormones in binge eating risk.

RECENT FINDINGS

Studies are few in number and findings are mixed, with only some studies showing increased binge eating during midlife and the menopausal transition. Sensitivity to ovarian hormones, potentially through gene x hormone interactions, may influence who experiences increased binge eating risk and could help explain mixed findings in the field. Future studies of hormone sensitivity and gene x hormone interactions are needed to further elucidate midlife and menopausal risk for binge eating in women.

Combined oral contraceptive use and risk for binge eating in women: Potential gene × hormone interactions

Extant animal and human data suggest endogenous ovarian hormones increase risk for binge eating in females, possibly via gene × hormone interactions and hormonally induced increases in genetic influences. Approximately 85 % of women will take combined oral contraceptives (COCs) that mimic the riskiest hormonal milieu for binge eating (i.e., post-ovulation when both estrogen and progesterone are present). The purpose of this narrative review is to synthesize findings of binge eating risk in COC users. Few studies have been conducted, but results suggest that COCs may increase risk for binge eating and related phenotypes (e.g., craving for sweets), particularly in genetically vulnerable women. Larger, more systematic human and animal studies of COCs and binge eating are needed. The goal of this work should be to advance personalized medicine by identifying the extent of COC risk as well as the role of gene × hormone interactions in susceptibility.

CXCL8(3-72) K11R/G31P protects against sepsis-induced acute kidney injury via NF-κB and JAK2/STAT3 pathway

Background

Acute kidney injury (AKI), which is mainly caused by sepsis, has high morbidity and mortality rates. CXCL8_(3–72) K11R/G31P (G31P) can exert therapeutic effect on inflammatory diseases and malignancies. We aimed to investigate the effect and mechanism of G31P on septic AKI.

Methods

An AKI mouse model was established, and kidney injury was assessed by histological analysis. The contents of serum creatinine (SCr) and blood urea nitrogen (BUN) were measured by commercial kits, whereas neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) were detected by enzyme-linked immunosorbent assay (ELISA) kits. The expressions of CXCL8 in serum and kidney tissues were determined using ELISA and immunohistochemical analysis, respectively. Apoptosis rate of renal tissue was detected by terminal deoxynucleotidyl transfer-mediated dUTP nick end labeling (TUNEL) analysis. The expressions of inflammatory cytokines were measured by quantitative real-time PCR and Western blot, respectively. The apoptosis-related proteins, JAK2, STAT3, NF-κB and IκB were determined by Western blot.

Results

G31P could reduce the levels of SCr, BUN, HGAL and KIM-1 and inhibit the renal tissue injury in AKI mice. G31P was also found to suppress the serum and nephric CXCL8 expressions and attenuated the apoptosis rate. The levels of inflammatory cytokines, pro-apoptotic proteins were decreased, while the anti-apoptotic proteins were increased by G31P in AKI mice. G31P also inhibited the activation of JAK2, STAT3 and NF-κB in AKI mice.

Conclusion

These results suggest that G31P could protect renal function and attenuate the septic AKI. Our findings provide a potential target for the treatment of AKI.

What do we know about sex differences in depression: A review of animal models and potential mechanisms

Clinical studies have shown that women are more susceptible to depression than men. Sex differences in depression have been associated with social, cultural, as well as biological factors. In spite of extensive preclinical studies in animal models for depression that have been used for understanding the mechanisms of the disease as well as for new drug development, a substantive lack of attention on sex-specific phenotypes in depression might mask the effect of sex on the outcome. In this review article, we summarize findings on the influence of sex on behavior in the most commonly used animal models for depression. We also discuss the potential underlying mechanisms of such sex-dependent variation in the phenotype, particularly in the neuroendocrine system.

Effects of progesterone on the neonatal brain following hypoxia-ischemia

Progesterone displays a strong potential for the treatment of neonatal hypoxic-ischemic encephalopathy since it has been shown to be beneficial in the treatment of the central nervous system injuries in adult animals. Here, we evaluated the effects of the administration of progesterone (10 mg/kg) in seven-days-old male Wistar rats submitted to neonatal hypoxia-ischemia (HI). Progesterone was administered immediately before ischemia and/or 6 and 24 h after the onset of hypoxia. The body weight of the animals, the volume of brain lesion and the expression of p-Akt and procaspase-3 in the hippocampus were evaluated. All animals submitted to HI showed a reduction in the body weight. However, this reduction was more remarkable in those animals which received progesterone before surgery. Administration of progesterone was unable to reduce the volume of brain damage caused by HI. Moreover, no significant differences were observed in the expression of p-Akt and procaspase-3 in animals submitted to HI and treated with either progesterone or vehicle. In summary, progesterone did not show a neuroprotective effect on the volume of brain lesion in neonatal rats submitted to hypoxia-ischemia. Furthermore, progesterone was unable to modulate p-Akt and procaspase-3 signaling pathways, which may explain the absence of neuroprotection. On the other hand, it seems that administration of progesterone before ischemia exerts some systemic effect, leading to a remarkable reduction in the body weight.

4'-Chlorodiazepam is neuroprotective against amyloid-beta in organotypic hippocampal cultures

The translocator protein (TSPO) is an outer mitochondrial membrane protein involved in the transport of cholesterol into the mitochondria, which is the first step for the synthesis of steroid hormones, as well as in the regulation of mitochondrial permeability transition pore opening and apoptosis. Studies have shown that the activation of TSPO may promote neuroprotective actions in experimental models of neurodegeneration and brain injury. In a previous study, our group showed that 4'-chlorodiazepam (4'-CD), a TSPO ligand, was neuroprotective against amyloid-beta (Aβ) in SHSY-5Y neuroblastoma cells. The aim of this study was to evaluate if 4'-CD was also neuroprotective against Aβ in organotypic hippocampal cultures and to identify its mechanisms of action. Aβ decreased the cell viability of organotypic hippocampal cultures, while 4'-CD had a neuroprotective effect when administered at 100nM and 1000nM. The neuroprotective effects of 4'-CD against Aβ were associated with an increased expression of superoxide dismutase (SOD). No differences were found in the expression of catalase, glial fibrillary acidic protein, Akt and procaspase-3. In summary, our results show that 4'-CD is neuroprotective against Aβ by a mechanism involving the modulation of SOD protein expression.

RU486 facilitates or disrupts the sensitization of sexual behaviors by estradiol in the ovariectomized Long-Evans rat: Effect of timecourse

An acute injection of estradiol benzoate (EB) to the ovariectomized (OVX) rat activates low levels of lordosis, and subsequent progesterone (P) administration augments lordosis and recruits a complete pattern of sexual behavior including appetitive behaviors (e.g., hops/darts and solicitations). However, repeated injections of 5μg or 10μg EB (but not 2μg EB), administered every 4days to sexually-experienced OVX rats results in a behavioral sensitization, such that lordosis quotients (LQs) and appetitive behaviors progressively increase. We have shown that adrenal P does not play a critical role because behavioral sensitization to EB is not prevented by adrenalectomy. Here we tested whether P receptors play a role by examining the effect of chronic administration of the P receptor antagonist RU486 at a dose that reliably inhibits sexual behavior in fully primed OVX rats. Females were treated with EB (5 or 10μg), and 5mg RU486 dissolved in 0.4mL vehicle (VEH; 80% sesame oil, 15% benzyl benzoate, 5% benzyl alcohol) 48h and 5h prior to each of 7 tests, respectively, occurring at 4-day intervals in unilevel 4-hole pacing chambers. Control animals were treated with 2, 5, or 10μg EB+VEH. As expected, sensitization did not occur in females treated with 2μg EB+VEH, and those females received fewer intromissions and ejaculations than all other groups. RU486 did not prevent the sensitization of LQ, moderate and high lordosis magnitudes (LM2 and LM3) or appetitive sexual behaviors on early tests, and in fact potentiated appetitive behaviors, LQ, LM2 and LM3, consistent with its facilitative actions in females treated with EB-alone, as we and others have reported previously. However, despite the initial facilitation, blocking P receptors by chronic administration of RU486 inhibited the maintenance of behavioral sensitization to EB.

Asymmetric effects of low doses of progesterone on GABA(A) receptor α4 subunit protein expression in the olfactory bulb of female rats

The aim of this study was to evaluate the effect of progesterone on the protein expression of α4 subunit of GABA(A) receptor, serotonin transporter (SERT), Akt, Erk, and caspase-3 in the olfactory bulb (OB) of female rats exposed to the forced swimming test (FST). Female rats were injected daily with progesterone (0.4 mg/kg body mass) or vehicle during 2 complete oestrous cycles and exposed to the FST, and the protein expression of GABA(A) receptor α4 subunit, SERT, Akt, Erk, and caspase-3 in the OB were evaluated. Progesterone increased the expression of the α4 subunit in the right OB and decreased its expression in the left OB, although it did not change the expression of other proteins. In summary, our findings indicate that progesterone has an asymmetric modulatory effect on the expression of GABA(A) receptor α4 subunit in the OB. This effect could be related to the antidepressant-like effect of progesterone in female rats.