Underlying mechanisms behind the protective effect of angiotensin (1–7) in experimental rat model of ovarian ischemia reperfusion injury

The Role of Mannitol and Vitamin D in Ovarian Ischemia/Reperfusion Injury in Rats with Acute Abdominal

This study was designed to investigate the effects of vitamin D and mannitol in an experimental rat ovarian torsion model. Thirty-two female Wistar albino rats were randomly classified as group 1: (sham), group 2: (detorsion), group 3: (detorsion + mannitol), group 4: (detorsion + vitamin D) and group 5: (detorsion + mannitol + vitamin D) (for each group n = 8). All groups were subjected to bilateral adnexal torsion for 2 h except for group 1. Bilateral adnexal detorsion was performed in all groups except for group 1. Groups 3 and 5 intraperitoneally received the injection of mannitol at a dose of 0.3 mg/kg 30 min before detorsion. Also, the group's 4 and 5 orally received vitamin D in a dose of 500 IU/kg/day for two weeks before torsion. Total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI) and proliferating cell nuclear antigen (PCNA) levels were analyzed. According to the histopathological analyses, ovarian tissue damage and follicle counting were evaluated. TOS, OSI and histopathologic score values of ovarian tissue were significantly lower in group 5 than groups 2, 3 and 4 (p < 0.05). The PCNA level was significantly higher in group 5 than in groups 2, 3 and 4 (p < 0.05). A strong negative correlation was found between OSI and PCNA in groups 2, 3, 4 and 5 (r = -0.92, p = 0.01; r = -0.98, p < 0.0001; r = -0.98, p < 0.0001 and r = -0.96, p = 0.0002, respectively). The numbers of primordial follicles in group 5 (p < 0.001) and primary follicles in group 4 (p < 0.001) were significantly higher when compared to group 2. Based on the results of this study, it could be suggested that combination treatment of mannitol with vitamin D is more effective in reversing tissue damage induced by ischemia-reperfusion (I/R) injury in the ovarian torsion model than administration of only an agent.

2-Arachidonoylglycerol Activity in Over Ischemia Reperfusion Damage: Can Endocannabinoids Protect Ovarian Reserve?

Objective: The present study aimed to demonstrate the possible effects of increased 2-arachidonoylglycerol (2-AG) by applying the monoacylglycerol lipase inhibitor KML-29 on rats with ovarian ischemia-reperfusion (IR) model. Methods: Forty-eight female Wistar albino rats were divided into six groups. Group 1: Sham, Group 2: Ischemia, Group 3: IR, Group 4: IR + KML-29 (2 mg/kg), Group 5: IR + KML-29 (20 mg/kg), and Group 6: IR + vehicle (dimethyl sulfoxide). Three hours of ischemia followed by 3 h of reperfusion. Two different doses of KML-29 (2 and 10 mg/kg) were administered intraperitoneally in Groups 4 and 5, 30 min before reperfusion. Ovarian IR injury and ovarian reserve were evaluated histopathological and by using nuclear factor (NF)-κB, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, superoxide dismutase, glutathione peroxidase pre-/postoperative blood antimullerian hormone, and inhibin B. Results: In the KML-1 and KML-2 groups, this damage was significantly reduced compared to the ischemia group. NF-κB, IL-1β, TNF-α, and TGF-β1 immunoreactivities increased statistically significantly in the ischemia group compared to the control group (p<0.001). Immunoreactivities of these proteins were significantly decreased in the KML-1 and KML-2 groups (p<0.001). It was observed that the number of these apoptotic cells decreased significantly in the KML-1 and KML-2 groups compared to the ischemia group (p<0.001). The postoperative inhibin level showed a significant decrease in the ischemia group compared to the sham group, while a significant increase was observed in the KML-1 and KML-2 groups compared to the ischemia group. Conclusion: It was seen that anti-inflammatory, antioxidant, and antiapoptotic activity was formed, and the ovarian reserve was preserved with 2-AG in ovarian IR damage. The protective effect of endocannabinoids on the ovaries may create a promising new treatment strategy for many pathologies that will affect the ovarian reserve.

Protective effects of esculetin against ovary ischemia-reperfusion injury model in rats

AIMS

Ovarian ischemia-reperfusion (I/R) injury is a phenomenon that necessitates urgent intervention, which occurs as a result of ovarian torsion, and it is frequently seen in young women. A large amount of free radical and oxidative damage as a result of I/R plays a role in the cause of the incident. Antioxidant agents are thought to be beneficial in preventing this damage, and the potential protective effects of esculetin, which had not been tested previously, were investigated in this study.

STUDY DESIGN

The rats in the study were divided into five groups at random: control, sham, esculetin, I/R, and treatment. Oxidative stress parameters, proinflammatory cytokines, nuclear factor erythroid 2-related factor 2 (Nrf-2)/nuclear factor-kβ (NF-κβ) pathway, and histopathological analyses were evaluated at the end of the study.

KEY FINDINGS

After I/R, malondialdehyde levels, proinflammatory cytokines, tumor necrosis factor-α and interleukin-1β levels and NF-κβ expressions were increased, Nrf-2 expression and glutathione level decreased and the histopathologic picture deteriorated. However, as a result of the esculetin treatment, ameliorative effects in the aforementioned parameters were determined, and it was ensured that they returned to normal levels.

CONCLUSION

According to these findings, esculetin has protective effects on I/R damage by lowering lipid peroxidation and having antioxidant and anti-inflammatory properties.

SIGNIFICANCE

Our results proved the protective effect of esculetin against ovarian IR injury in rats and this may be attributed to Nrf-2/NF-κβ axis which showed antioxidant and anti-inflammatory effects. Therefore, esculetin can be used in the future for preventive effects to ovarian IR injury.

Targeting PI3K/p-Akt/eNOS, Nrf2/HO-1, and NF-κB/p53 signaling pathways by angiotensin 1-7 protects against liver injury induced by ischemia-reperfusion in rats

The liver is an important organ, and hepatic ischemia-reperfusion (IR) injury is a frequent pathophysiological process that can cause significant morbidity and mortality. Thus, our study aimed to investigate the effect of targeting PI3K/p-Akt/eNOS (phosphoinositide 3-kinase/phospho-protein kinase B/endothelial nitric oxide synthase), Nrf2/HO-1 (nuclear factor-erythroid 2-related factor-2/heme oxygenase-1), and NF-κB/p53 (nuclear factor-κB/tumor protein 53) signaling pathways by using angiotensin (1-7) [ang-(1-7)] against hepatic injury induced by IR. Thirty-two male rats were included in sham group, ang-(1-7)-treated group, hepatic IR group, and hepatic IR group treated with ang-(1-7). The levels of hepatic ang-(1-7), angiotensin II (Ang II), angiotensin-converting enzyme 2 (ACE2), HO-1, malondialdehyde (MDA), PI3K, and p-Akt were assessed. The expressions of eNOS and B-cell leukemia/lymphoma-2 (BCL-2) in the liver were determined. Histological assessment and immunohistochemical expression of NF-κB, p53, and Nrf2 were carried out. The levels of reduced glutathione (GSH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in serum were estimated. Results showed that administration of ang-(1-7) to hepatic IR rats led to significant amelioration of hepatic damage through a histological evaluation that was associated with significant upregulation of the expressions of PI3K/p-Akt/eNOS and Nrf2/HO-1 with downregulation of NF-κB/p53 signaling pathways. In conclusion, PI3K/p-Akt/eNOS and Nrf2/HO-1 signaling pathways are involved in the protective effects of ang-(1-7) against hepatic damage induced by IR. Therefore, ang-(1-7) can be used to prevent hepatic IR, which occurs in certain conditions such as liver transplantation, hemorrhagic shock, and severe infection.

Angiotensin 1-7 mitigates rhabdomyolysis induced renal injury in rats via modulation of TLR-4/NF-kB/iNOS and Nrf-2/heme‑oxygenase-1 signaling pathways

AIMS

Rhabdomyolysis (RM) is a critical condition with a high mortality rate, but effective management is still deficient. Till date, there are no studies that have addressed the effect of angiotensin 1-7 in this condition, hence, the rationale of this study was to evaluate the potential protective effect of Angiotensin 1-7 (Ang1-7), on rhabdomyolysis (RM) induced kidney injury in rats and detecting the underlying mechanistic insights.

MAIN METHODS

Forty adult male albino rats were divided into groups; the control group, RM group, RM+Ang1-7 group, and RM+Ang1-7+ A779 group. Sera and urine samples were collected for analysis of renal and muscle injury markers. Kidney tissues were taken for estimation of oxidative, inflammatory, and apoptotic markers as well as angiotensin-II (Ang II) and Ang1-7. Renal histology and expression of inducible nitric oxide synthase-1 (iNOS), real-time PCR for angiotensin-converting enzyme-2 (ACE-2), nuclear erythroid factor-2 (Nrf-2), Toll like receptor 4 (TLR-4) and NF-kB in kidney tissues were also measured.

KEY FINDINGS

Induction of RM caused renal oxidative stress injury, inflammation, apoptosis and marked deterioration in kidney functions as well as reduction of Ang1-7 and raised Angiotensin-II level in kidney tissues. Administration of Ang1-7 to the RM group reversed all the affected parameters which were blocked by A779 administration (Mas receptor blocker).

SIGNIFICANCE

We concluded that Ang1-7 could be a potential therapeutic agent that could mitigate RM-induced renal injury. The underlying mechanisms may involve Stimulation of the ACE-2/Ang1-7/MasR axis and modulation of TLR-4/NF-kB/iNOS and Nrf-2/heme‑oxygenase -1 pathways.

Administration of hemin ameliorates ovarian ischemia reperfusion injury via modulation of heme oxygenase-1 and p-JNK/p-NF-κBp65/iNOS signaling pathway

AIMS

Ovarian torsion is the fifth common gynecological emergency that can affect females of all ages particularly during reproductive age and its management by detorsion leads to ovarian ischemia reperfusion (IR) injury. Therefore, prophylactic measures are required to protect the ovarian function after detorsion. So that, our study aimed to assess the effect and underlying mechanisms of heme oxygenase-1 (HO-1) inducer; hemin against ovarian damage induced by IR injury in rats.

MAIN METHODS

Female rats were divided into: sham group, hemin group, ovarian IR (OIR) groups with and without hemin treatment. Serum levels of reduced glutathione (GSH) and interleukin 1 β (IL-1β) were measured in addition to ovarian levels of malondialdehyde (MDA), nitric oxide (NO) and superoxide dismutase (SOD). Ovarian phospho-Janus kinase (p-JNK) levels and gene expressions of HO-1 and inducible nitric oxide synthase (iNOS) were determined. Moreover, histopathological changes and expressions of phospho-nuclear factor kappa B p65 (p-NF-κB p65) and cleaved caspase-3 were done.

KEY FINDINGS

Treatment of OIR rats with hemin led to significant attenuation of ovarian damage through histological examination which was associated with significant increase in ovarian expression of HO-1, ovarian SOD and serum GSH levels with significant decrease in ovarian p-JNK levels, expressions of p-NF-κB p65, iNOS and cleaved caspase-3 in addition to serum IL-1β levels.

SIGNIFICANCE

The protective effect of hemin can be attributed to the increased expression of HO-1 which showed antioxidant, anti-inflammatory and anti-apoptotic effects. Therefore, hemin can be administered to prevent ovarian IR injury which occurs after detorsion.

Protective effect of hydrogen sulfide against stress-induced lung injury: involvement of Nrf2, NFκB/iNOS, and HIF-1α signaling pathways

Stress is a common phenomenon that is attracting increasing attention. Hydrogen sulfide (H2S) is a gasotransmitter that plays an important role in many physiological and pathological events. Our study aimed to estimate the effect and the underlying mechanisms of the H2S donor, sodium hydrosulfide (NaHS), against immobilization stress (IS)-induced lung injury. Forty adult male rats were classified into control group, NaHS group, and IS groups with and without NaHS treatment. Serum was obtained to determine corticosterone (CORT), total antioxidant capacity (TAC), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) levels. Lung H2S, nitric oxide (NO), inducible nitric oxide synthase (iNOS), and malondialdehyde (MDA) levels were measured. Lung expressions of H2S synthesizing enzymes and Western blot analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) and hypoxia-inducible factor 1 alpha (HIF 1α) were estimated. Histopathological changes and immunohistochemical assessment of nuclear factor kappa B (NF-κB) and caspase-3 were also done. Pretreatment with NaHS led to marked histological protection from lung damage seen in IS rats. Furthermore, pretreatment with NaHS before IS protected lung H2S levels and expressions of H2S-synthesizing enzymes. Similarly, the levels of CORT, TNF-α, IL-10, MDA, TAC, NO, iNOS, HIF-1 α, and nuclear Nrf2 and expressions of NF-kB and caspase 3 were all maintained at near control levels in contrast to that in the IS rats. In conclusion, NaHS is protective against stress-induced lung injury due to its antioxidant, anti-inflammatory, anti-fibrotic, and antiapoptotic effects. Thus, NaHS can be used to minimize stress complications on lung.

Evaluation of the protective effects of gossypin for ischemia/reperfusion injury in ovary tissue

AIM

Ovarian ischemia-reperfusion (I/R) injury is a serious gynecological condition that affects women of reproductive age and reduces ovarian reserve. Management of I/R injury with detorsion causes reperfusion damage, in which oxidative stress plays a central role. This study aimed to investigate whether the gossypin (GOS) with antioxidant properties, a flavonoid, has beneficial effects on the biochemical, molecular, and histopathological aspects of ovarian I/R injury.

METHODS

Thirty-three female Balb/c mice were randomly divided into five groups as follows: Healthy (Sham-operated control group), I/R (IR group), I/R + GOS 5 (I/R with GOS 5 mg/kg), I/R + GOS 10 (I/R with GOS 10 mg/kg), and I/R + GOS 20 (I/R with GOS 20 mg/kg). This was followed by 3 h of ischemia and subsequent reperfusion for 3 h after detorsion was exposed. GOS was injected 2 h before reperfusion.

RESULTS

IL-1β, IL-6, TNF-α, NF-κB, and CASP-3 mRNA expressions, SOD (superoxide dismutase) activity, GSH (glutathione), and MDA (malondialdehyde) levels, and histopathological changes were evaluated in ovarian tissue. Histological examination indicated that treatment of ovarian I/R injury with GOS led to the improvement of ovarian tissue, which was accompanied by an increase in SOD activity and GSH level and a decrease in MDA level, NF-κB, TNF-α, IL-1β, and IL-6 expressions. GOS was also corrected by reducing the elevated expression of CASP-3 as apoptosis-change marker.

CONCLUSION

These findings indicate that the treatment of GOS may be useful as a conservative approach to reverse I/R injury via amelioration of oxidative stress parameters and histopathological scores, attenuation of inflammation, and the suppression of apoptosis.

Complication and Sequelae of COVID-19: What Should We Pay Attention to in the Post-Epidemic Era

COVID-19 is widespread worldwide and seriously affects the daily life and health of humans. Countries around the world are taking necessary measures to curb the spread. However, COVID-19 patients often have at least one organ complication and sequelae in addition to respiratory symptoms. Controlling the epidemic is only a phased victory, and the complication and sequelae of COVID-19 will need more attention in the post-epidemic era. We collected general information from over 1000 articles published in 2020 after the COVID-19 outbreak and systematically analyzed the complication and sequelae associated with eight major systems in COVID-19 patients caused by ACE2 intervention in the RAS regulatory axis. The autoimmune response induced by 2019-nCoV attacks and damages the normal tissues and organs of the body. Our research will help medical workers worldwide address COVID-19 complication and sequelae.

Angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7) and Mas receptor in gonadal and reproductive functions

Angiotensin (Ang)-(1-7) is an active peptide formed from Ang I or Ang-(1-9) by multiple proteolytic steps involving angiotensin-converting enzyme (ACE) 1 and other peptidases, or by a single cleavage of Ang II catalyzed chiefly by ACE2. The effects of Ang-(1-7) are mediated by the G protein-coupled receptor Mas (or Mas1), encoded by the protooncogene MAS. The reproductive system expresses ACE2 quite abundantly and therefore is able to generate Ang-(1-7) using precursor peptides produced locally or taken from circulation. In several mammalian species, Ang-(1-7) stimulates ovarian follicle growth, oocyte maturation and ovulation. The peptide is found in human endometrium, mostly during the secretory phase of menstrual cycle when the uterus is receptive to embryo implantation. Rat models and human observational studies suggest that Ang-(1-7) is part of the maternal adaptive response to pregnancy and its deficiency is associated with poor circulation in the placental bed. Knockout mice revealed a relevant participation of Mas-mediated stimulus to the maintenance of normal spermatogenesis, even though the animal can still reproduce without it. In addition, the vasorelaxant effect of Ang-(1-7) participates in the physiological mechanism of corpus cavernosum blood influx and penile erection. We conclude that preclinical evidence encourages the pursuit of treatments for female and male reproductive dysfunctions based on Mas agonists, starting with its natural ligand Ang-(1-7).

Protective effects of nebivolol on ovarian ischemia-reperfusion injury in rat

AIM

Ovarian torsion is a common gynecological emergency of reproductive ages, occurring at rates of 2.7-7.4%. This study aimed to evaluate the antioxidant effects of Nebivolol (NEB) and histopathological changes in experimental ischemic (I) and ischemic-reperfusion (I/R) injury in rat ovaries.

METHODS

Forty-eight adult female rats were randomly separated into six groups as group 1 (control) receiving an oral saline solution for 3 days; group 2 (I) that underwent ischemia for 3 h with the application of atraumatic vascular clips; group 3 (I/R); group 4 (I + NEB) receiving 10 mg/kg NEB by oral gavage 30 min prior to the ischemia induction; group 5 (I/R + NEB) receiving 10 mg/kg NEB, and group 6 (control + NEB) receiving oral 10 mg/kg NEB for 3 days before ischemia induction followed by consequent reperfusion. Ovarian tissue damage was scored by histopathological analysis. Ovarian tissue malondialdehyde (MDA) and glutathione (GSH) levels were measured biochemically.

RESULTS

The levels of MDA and tumor necrosis factor-alpha (TNF-α), and TUNEL assay positivity scores increased in the I and I/R groups. GSH levels decreased in all case groups (P < 0.05). The oral administration of NEB (10 mg/kg) to the I- and I/R-groups reduced the levels of MDA and TNF-α and TUNEL assay immunopositivity scores (P < 0.05). GSH levels increased in the treatment groups.

CONCLUSION

The current experimental ovarian torsion study suggests a protective role for NEB against I and I/R injury in rat ovaries. NEB may be a novel agent for decreasing ovarian I/R injury.