Selection of antioxidants against ovarian oxidative stress in mouse model

Tannic acid alleviates 3-nitropropionic acid-induced ovarian damage in Brandt's vole (Lasiopodomys brandtii)

Tannic acid (TA) is a polyphenol with antioxidant properties present in various plants. In this study, we explored the protective effect of TA against ovarian oxidative stress in Brandt's voles and its underlying mechanism. At various doses, 3-nitropropionic acid (3-NPA) was intraperitoneally injected into Brandt's voles to simulate ovarian oxidative stress. Thereafter, various doses of TA were intragastrically administered to examine the protective effect of TA against 3-NPA-induced ovarian damage. Changes in inflammation, autophagy, apoptosis, and oxidative stress-related factors were investigated through various biochemical and histological techniques. Ovarian oxidative stress was successfully induced by the intraperitoneal administration of 12.5 mg/kg 3-NPA for 18 days. As a result, the ovarian coefficient decreased and ovarian tissue fibrosis was induced. TA treatment effectively alleviated the increase in luteinizing hormone and follicle-stimulating hormone levels; the decrease in estradiol, progesterone, and anti-Müllerian hormone levels; and the decline in fertility induced by 3-NPA. Compared to that in the 3-NPA group, TA decreased the expression of autophagy-related proteins beclin-1 and LC3, as well as the level of apoptosis. It also activated the AKT/mTOR signaling pathway, downregulated PTEN and p-NF-κB expression, and upregulated Nrf2 expression. In conclusion, our findings indicate that TA could inhibit autophagy via the regulation of AKT/mTOR signaling, suppressing oxidative damage and inflammatory responses through Nrf2 to alleviate 3-NPA-induced ovarian damage. Collectively, the current findings highlight the protective effects of TA in Brandt's vole, where it promotes the maintenance of normal ovarian function.

Curcumin and gallic acid have a synergistic protective effect against ovarian surface epithelium and follicle reserve damage caused by autologous intraperitoneal ovary transplantation in rats

The objective of this study to examine the effects of curcumin and gallic acid use against oxidative stress damage in the autologous intraperitoneal ovarian transplantation model created in rats on ovarian follicle reserve, ovarian surface epithelium, and oxidant-antioxidant systems. 42 adult female Sprague Dawley rats (n=7) were allocated into 6 groups. Group 1 served as the control. In Group 2, rats underwent ovarian transplantation (TR) to their peritoneal walls. Group 3 received corn oil (CO) (0.5 ml/day) one day before and 14 days after transplantation. Group 4 was administered curcumin (CUR) (100 mg/kg/day), Group 5 received gallic acid (GA) (20 mg/kg/day), and Group 6 was treated with a combination of curcumin and gallic acid via oral gavage after transplantation. Rats were sacrificed on the 14th postoperative day, and blood along with ovaries were collected for analysis. The removed ovaries were analyzed at light microscopic, fluorescence microscopic, and biochemical levels. In Group 2 and Group 3, while serum and tissue Total Oxidant Levels (TOS) and Oxidative Stress Index (OSI) increased, serum Total Antioxidant Levels (TAS) decreased statistically significantly (p˂0.05) compared to the other groups (Groups 1, 4, 5, and 6). The ovarian follicle reserve was preserved and the changes in the ovarian surface epithelium and histopathological findings were reduced in the antioxidant-treated groups (Groups 4, 5, and 6). In addition, immunofluorescence examination revealed that the expression of Cytochrome C and Caspase 3 was stronger and Ki-67 was weaker in Groups 2 and 3, in comparison to the groups that were given antioxidants. It can be said that curcumin and gallic acid have a histological and biochemical protective effect against ischemia-reperfusion injury due to ovarian transplantation, and this effect is stronger when these two antioxidants are applied together compared to individual use.

Ningxin-Tongyu-Zishen formula alleviates the senescence of granulosa cells on D-galactose-induced premature ovarian insufficiency mice

Ningxin-Tongyu-Zishen formula (NTZF) is a clinical experience formula for the treatment of premature ovarian insufficiency (POI) in traditional Chinese medicine (TCM), and the potential mechanism is unknown. For in vivo experiments, POI mouse models (C57BL/6 mice), were constructed by subcutaneous injection of D-galactose (D-gal, 200 mg/kg). After treatment of NTZF (10.14, 20.27, 40.54 g/kg;) or estradiol valerate (0.15 mg/kg), ovarian function, oxidative stress (OS) and protein expression of Sirt1/p53 were evaluated. For in vitro experiments, H2O2 (200 μM) was used to treat KGN to construct ovarian granulosa cells (OGCs) cell senescence model. Pretreatment with NTZF (1.06 mg/mL) or p53 inhibitor (Pifithrin-α, 1 μM) was performed before induction of senescence, and further evaluated the cell senescence, OS, mRNA and protein expression of Sirt1/p53. In vivo, NTZF improved ovarian function, alleviated OS and Sirt1/p53 signaling abnormalities in POI mice. In vitro experiments showed that NTZF reduced the level of OS and alleviated the senescence of H2O2-induced KGN. In addition, NTZF activated the protein expression of Sirt1, inhibited the mRNA transcription and protein expression of p53 and p21. Alleviating OGCs senescence and protecting ovarian function through Sirt1/p53 is one of the potential mechanisms of NTZF in the treatment of POI.

Ameliorative effect of gallic acid on cisplatin-induced ovarian toxicity in rats

The aim of the present study was to evaluate the protective effect of gallic acid (GA) against cisplatin (CDDP)-induced ovarian toxicity, for the first time. The ovarian damage was generated with CDDP (5 mg/kg) intraperitoneally (i.p.) administration in rats. GA (2.5 and 5 mg/kg) were administered i.p. for 3 consecutive days. The study was carried out in 5 main groups containing 6 rats in each group: control, GA (5 mg/kg), CDDP, CDDP + GA (2.5 mg/kg) and CDDP + GA (5 mg/kg). The levels of ovarian malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), catalase (CAT), 8-hydroxy-2'-deoxyguanosine (8-OHdG), caspase-3 and tumor necrosis factor-alpha (TNF-α) were determined. Hematoxylin and eosin staining method was employed for the histopathological examination. In the CDDP group, it is determined that statistically significant decreasing in the levels of TAS and CAT, and increasing in the levels of MDA, TOS, OSI, 8-OHdG, caspase-3 and TNF-α (p < 0.05) compared with control group. GA administrations statistically significantly restored this damage (p < 0.05). Although vascular congestion, edema, hemorrhage, follicular degeneration and leukocyte infiltration were significantly higher in the CDDP group than in the control group, GA administrations statistically significantly restored these damages (p < 0.05). In conclusion, this study showed that GA prevented CDDP-induced ovarian damage with its antioxidant, anti-apoptotic and anti-inflammatory activities. More comprehensive studies are needed to see the underlying mechanisms.

Protective effect of gallic acid on doxorubicin-induced ovarian toxicity in mouse

The aims of the present study were to evaluate the protective effects of gallic acid against doxorubicin-induced ovarian toxicity in mice, and to verify the possible involvement of PI3K and mTOR signaling pathway members (PTEN, Akt, FOXO3a and rpS6) in the gallic acid protective actions. Mice were pretreated with NaCl (0.15 M, p.o.) (control and doxorubicin groups) or gallic acid (50, 100 or 200 mg/kg body weight, p.o.) once daily, for 5 days, and on the third day of treatment, after 1 h of treatment administration, the mice received saline solution (i.p.) (control group) or doxorubicin (10 mg/kg of body weight, i.p.). Next, the ovaries were harvested for histological (follicular morphology and activation), fluorescence (GSH and mitochondrial activity), and immunohistochemical (PCNA, cleaved caspase-3, TNF-α, p-PTEN, Akt, p-Akt, p-rpS6 and p-FOXO3a) analyses. The results showed that cotreatment with 50 mg/kg gallic acid plus doxorubicin preserved the percentage of normal follicles and cell proliferation, reduced the percentage of cleaved caspase-3 follicles, prevented inflammation, and increased GSH concentrations and mitochondrial activity compared to doxorubicin treatment alone. Furthermore, cotreatment 50 mg/kg gallic acid plus doxorrubicin increased expression of Akt, p-Akt, p-rpS6 and p-FOXO3a compared to the doxorubicin alone. In conclusion, 50 mg/kg gallic acid protects the mouse ovary against doxorubicin-induced damage by improving GSH concentrations and mitochondrial activity and cellular proliferation, inhibiting inflammation and apoptosis, and regulating PI3K and mTOR signaling pathway.

He's Yangchao Recipe Ameliorates Ovarian Oxidative Stress of Aging Mice under Consecutive Superovulation Involving JNK- And P53-Related Mechanism

Objective

To evaluate the effects of He's Yangchao Recipe (HSYC) on ameliorating ovarian oxidative stress of aging mice under consecutive superovulation.

Methods

An 8-month-old C57BL/6 female mouse was chosen to establish an aging model under ovarian hyperstimulation. Mice were randomly separated into four groups: R1 as the control group, R4 as the model group, NR4 with N-acetyl-L-cysteine (NAC) administration, and TR4 with HSYC administration. Oocyte collection, in vitro fertilization, and embryo culture were performed. The serum hormone levels were measured by enzyme-linked immunosorbent assays (ELISA); the reactive oxygen species (ROS) level of oocytes, the number of growing follicles, corpus luteum, ovulated oocytes, and developing embryos at each stage, along with the proportions of fragmented oocytes and abnormal mitochondria in granulosa cells (GCs) and the apoptosis rate of GCs were calculated; the mRNA and protein levels of JNK, P53, BAX were detected by real-time PCR and the Simple Western System.

Results

HSYC enhanced estradiol, progesterone, and inhibin-B levels and increased growing follicle and corpus luteum and ovulated egg counts compared to the R4 group (P < 0.05), whereas it decreased the proportions of fragmented oocytes (P < 0.01); Meanwhile, embryos from mice subjected to four superovulation cycles with HSYC treated had a higher hatching potential. The ROS level of oocytes is downregulated by HSYC (P < 0.01) and the percentage of abnormal mitochondrial in ovaries of the TR4 group was also significantly declined compared to the R4 group (P < 0.05); the most TUNEL-positive cells proportion was detected in the R4 group; nevertheless, HSYC effectively attenuated this detrimental effect (P < 0.05). The mRNA and protein expressions of JNK and P53 in ovary tissues were reduced in the TR4 group while these genes were upregulated by repeated superovulation (P < 0.05).

Conclusions

HSYC exerted promising effects on promoting the diminished ovarian reserve and decreased oocyte quality induced by both aging and consecutive ovarian superovulation, potentially via the ROS/JNK/p53 pathway.

Metabolomics-Based Profiling, Antioxidant Power, and Uropathogenic Bacterial Anti-Adhesion Activity of SP4TM, a Formulation with a High Content of Type-A Proanthocyanidins

Flavonoids and proanthocyanidins (PACs) have been the subject of intense scientific investigations, both for their antioxidant properties and anti-adhesion activity against uropathogenic bacteria. We investigated the metabolomics and antioxidant capacity of SP4^TM, a patent-pending formulation based on a mixture of plant extracts with a high content of bioactive PACs and other polyphenols. The total content of polyphenols (885.51 ± 14.19 mg/g), flavonoids (135.52 ± 8.98 mg/g), anthocyanins (54.84 ± 2.97 mg/g), and PACs (379.43 ± 12.44 mg/g) was quantified using UV-Vis assays. Use of HPLC-ESI-MS/MS revealed the presence of 5 flavanols (100.77 ± 3.90 mg g⁻¹ d.wt), 11 flavonols (59.96 ± 1.83 mg g⁻¹ d.wt), and 8 anthocyanins (46.96 ± 1.59 mg g⁻¹ d.wt), whereas MALDI-TOF MS showed that SP4^TM contains PACs with one or more type-A interflavan bonds at each degree of polymerization. Regarding antioxidant properties, LUCS technology on HepG2 cells evidenced the ability of SP4^TM to neutralize intracellular free radicals, inhibit membrane lipid peroxidation, quench H₂O₂, and reduce free radicals mainly through chelating mechanism, as demonstrated by a higher FRAP value (2643.28 ± 39.86 mmol/g) compared with ABTS (139.92 ± 6.16 mmol/g) and DPPH (89.51 ± 3.91 mmol/g). Finally, the SP4^TM type-A PAC content strongly prevented bacterial adhesion of P-fimbriated uropathogenic Escherichia coli (0.23 mg/mL). In conclusion, SP4^TM has a strong antioxidant capacity involving multitarget mechanisms and is a potential supplement to fight urinary tract infections due to its ability to inhibit uropathogenic E. coli adhesion.

p-Coumaric acid alleviates cisplatin-induced ovarian toxicity in rats

OBJECTIVE

The therapeutic value of cisplatin (CDDP) as an anticancer drug is limited by its ovo-otoxicity. The effect of natural phenolic acids in the prevention of many diseases related to oxidative stress has been reported. Here, the ability of p-coumaric (pCA) acid, a member of phenolic acids, to protect rat ovary tissue against CDDP-induced oxidative stress was investigated.

METHODS

The study was carried out in five main groups containing six rats in each group: control, pCA (4 mg/kg), CDDP, CDDP plus pCA (2 mg/kg), and CDDP plus pCA (4 mg/kg). The levels of ovarian malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), catalase (CAT), 8-hydroxy-2'-deoxyguanosine (8-OHdG), caspase-3, and tumor necrosis factor-alpha (TNF-α) were determined. Hematoxylin and eosin staining method was employed for the histopathological examination.

RESULTS

In the CDDP group, it is determined that statistically significant decreasing in the levels of TAS and CAT, and increasing in the levels of MDA, TOS, OSI, 8-OHdG, caspase-3, and TNF-α compared with control group (p < 0.05). pCA administration statistically significantly restored this damage in a dose-dependent manner (p < 0.05). Although vascular congestion, edema, hemorrhage, follicular degeneration, and leukocyte infiltration were significantly higher in the CDDP group than in the control group, pCA administrations statistically significantly restored these damages (p < 0.05).

CONCLUSIONS

The data presented here indicate that pCA protects ovarian tissues of rats against CDDP-induced oxidative stress, inflammation, and apoptosis. It may be worthy to consider the usefulness of pCA as adjuvant therapy in cancer management.

Protective effect of astaxanthin on experimental ovarian damage in rats

This study aimed to investigate the protective effect of astaxanthin (AS) on 3-nitropropionic acid (3-NPA) induced experimental ovarian damage in rats. Thirty two female Wistar rats were divided into four equal groups of eight each: control group (C); phosphate-buffered saline, AS group; AS (80 mg/kg) for 14 days, 3-NPA group; 3-NPA (6.25 mg/kg) twice a day for 7 days, 3-NPA + AS group; administered AS (80 mg/kg) for 14 days and 3-NPA (6.25 mg/kg) for 7 days. All injections were administered intraperitoneally. Rats were fed ad libitum with standard rat chow and tap water. Plasma and ovarian tissue total antioxidant capacity (TAC), total oxidant capacity (TOC) and oxidative stress index (OSI) levels, whole blood reduced glutathione (GSH), plasma paraoxonase 1 (PON1) activity, lipid profile, malondialdehyde (MDA), nitric oxide (NO), total sialic acid (TSA) and total thiol (TT) concentrations were analysed spectrophotometrically. Also, ovarian tissue histopathology was performed. We observed 3-NPA-induced histopathological ovarian damage significantly decreased the TAC (p < 0.001), GSH (p < 0.001), high-density lipoprotein (p < 0.01) levels and PON1 activity (p < 0.01), and significantly increased TOC, OSI (p < 0.001), MDA, NO, TSA, cholesterol, low-density lipoprotein (p < 0.01) and triglyceride (p < 0.05) levels. In conclusion, cotreatment with AS restored the negative effect of 3-NPA on all biochemical parameters cited above and improved the histopathological ovarian damage. Ovarian toxicity induced by 3-NPA might be due to oxidative damage. The improvement of AS seems to be related to its antioxidant properties.

Si-Wu-Tang facilitates ovarian function through improving ovarian microenvironment and angiogenesis in a mouse model of premature ovarian failure

ETHNOPHARMACOLOGICAL RELEVANCE

Premature ovarian failure (POF) is a severe illness, characterized by premature menopause with a markedly decrease in ovarian function, which leads to infertility. Si-Wu-Tang (SWT), also called "the first prescription of gynecology" by medical experts in China, is widely used as the basic formula in regulating the menstrual cycle and treating infertility. However, the potential effect and underlying mechanisms of action of SWT on the treatment of POF have not yet been elucidated.

PURPOSE

This study aimed to explore the therapeutic effect and underlying molecular mechanism of action of SWT on the treatment of POF in C57BL/6 mice.

MATERIALS AND METHODS

The main compounds of SWT were identified by high-performance liquid chromatography (HPLC). POF model groups were established by a single intraperitoneal injection of cyclophosphamide (Cy, 100 mg/kg). SWT or dehydroepiandrosterone (DHEA) were administered via oral gavage for 28 consecutive days. Ovarian function and pathological changes were evaluated by hormone levels, follicular development, and changes in angiogenesis. Furthermore, statistical analyses of fertility were also performed.

RESULTS

Treatment with SWT significantly improved estrogen levels, the number of follicles, antioxidant defense, and microvascular formation in POF mice. Moreover, SWT significantly activated the Nrf2/HO-1 and STAT3/HIF-1α/VEGF signaling pathways to promote angiogenesis, resulting in a better fertility outcome when compared to the model group.

CONCLUSIONS

Our findings indicated that SWT protected ovarian function of Cy-induced POF mice by improving the antioxidant ability and promoting ovarian angiogenesis, thereby providing scientific evidence for the treatment of POF using SWT.

The effect of light on follicular development in laying hens

OBJECTIVE

The oxidative stress status and changes of chicken ovary tissue after shading were studied, to determine the mechanism of the effect of shading on follicular development.

METHODS

Twenty healthy laying hens (40 weeks old) with uniform body weight and the same laying rate were randomly divided into two groups (the shading group and normal light group). In the shading group, the cage was covered to reduce the light intensity inside the cage to 0 without affecting ventilation or food intake. The normal lighting group received no additional treatment. After 7 days of shading, oxidative stress related indicators and gene expression were detected.

RESULTS

Analysis of paraffin and ultrathin sections showed that apoptosis of ovarian granulosa cells (GCs) increased significantly after light shading. Enzyme linked immunosorbent assay results revealed that the levels of total antioxidant capacity, malondialdehyde, superoxide dismutase (SOD), glutathione, catalase (CAT), and other substances in the sera, livers, ovaries, and follicular GCs of laying hens increased significantly after shading for 7 days; and reactive oxygen species (ROS) levels in the livers of laying hens also increased significantly. ROS in the serum, ovarian and GCs also increased. After shading for 7 days, the levels of 8-hydroxy-2 deoxyguanosine in the sera and ovarian tissues of laying hens increased significantly. Cell counting kit-8 detection showed that the proliferation activity of GCs in layer follicles decreased after shading for 7 days; the expression level of the anti-apoptotic gene B-cell lymphoma-2 in ovarian tissue and follicular GCs was significantly reduced, and the expression levels of pro-apoptotic caspase 3 (casp3), and SOD, glutathione peroxidase 2 (GPX2), and CAT were all significantly increased.

CONCLUSION

Oxidative stress induced by shading light has a serious inhibitory effect on follicular development during reproduction in laying hens.

Gallic acid promotes the in vitro development of sheep secondary isolated follicles involving the phosphatidylinositol 3-kinase pathway

This study was conducted to evaluate the effect of addition of gallic acid as the single antioxidant to the base medium for in vitro culture of sheep secondary follicles and if the phosphatidylinositol 3-kinase (PI3K) pathway is involved in the action of gallic acid. Secondary follicles were isolated and cultured for 12 days in α-MEM supplemented with bovine serum albumin (BSA), insulin, glutamine, hypoxanthine, transferrin, selenium, and ascorbic acid (control medium: α-MEM⁺) or in α-MEM supplemented with BSA, insulin, glutamine, hypoxanthine and different concentrations of gallic acid (25, 50 or 100 μM), thus replacing transferrin, selenium and ascorbic acid in the medium. Follicle morphology, glutathione (GSH), and mitochondrial activity, and meiotic resumption were evaluated. Furthermore, inhibition of PI3K pathway was performed by pretreatment with LY294002. After 12 days of culture, the follicle survival in a medium containing 100 μM gallic acid was similar (P > 0.05) to α-MEM⁺ and greater (P < 0.05) compared with other gallic acid concentrations. Antrum formation, follicle diameter, GSH, and mitochondrial activity, and meiotic resumption, however, were greater (P < 0.05) when 100 μM gallic acid was included in the α-MEM⁺ culture medium compared with the control medium. Furthermore, LY294002 inhibited (P < 0.05) follicle survival, development, and meiotic resumption stimulated by 100 μM gallic acid. In conclusion, concentration of 100 μM of gallic acid can be a substitute for transferrin, selenium, and ascorbic acid in the base medium during in vitro culture of sheep secondary follicles, inducing follicle development likely through the PI3K pathway.

Female Fertility and Environmental Pollution

A realistic picture of our world shows that it is heavily polluted everywhere. Coastal regions and oceans are polluted by farm fertilizer, manure runoff, sewage and industrial discharges, and large isles of waste plastic are floating around, impacting sea life. Terrestrial ecosystems are contaminated by heavy metals and organic chemicals that can be taken up by and accumulate in crop plants, and water tables are heavily contaminated by untreated industrial discharges. As deadly particulates can drift far, poor air quality has become a significant global problem and one that is not exclusive to major industrialized cities. The consequences are a dramatic impairment of our ecosystem and biodiversity and increases in degenerative or man-made diseases. In this respect, it has been demonstrated that environmental pollution impairs fertility in all mammalian species. The worst consequences are observed for females since the number of germ cells present in the ovary is fixed during fetal life, and the cells are not renewable. This means that any pollutant affecting hormonal homeostasis and/or the reproductive apparatus inevitably harms reproductive performance. This decline will have important social and economic consequences that can no longer be overlooked.

Integrated Analysis of miRNA-mRNA Interaction Network in Porcine Granulosa Cells Undergoing Oxidative Stress

Oxidative stress (OS), a common intracellular phenomenon induced by excess reactive oxygen species (ROS) generation, has been shown to be associated with mammalian ovarian follicular development blockage and granulosa cell (GC) impairment. However, the mechanism involved in these effects remains unknown, and the effect of OS on the transcriptome profiles in porcine GCs has not been fully characterized. In this study, we found that hydrogen peroxide-mediated oxidative stress induced porcine GC apoptosis and impaired cell viability. Moreover, RNA-seq analysis showed that oxidative stress induced dramatic changes in gene expression in porcine GCs. A total of 2025 differentially expressed genes (DEGs) were identified, including 1940 DEmRNAs and 55 DEmiRNAs. Functional annotation showed that the DEGs were mainly associated with cell states and function regulation. In addition, multiple hub genes (FOXO1, SOD2, BMP2, DICER1, BCL2L11, FZD4, ssc-miR-424, and ssc-miR-27b) were identified by constructing protein-protein interaction and DEmiRNA-DEmRNA regulatory networks. Furthermore, a gene-pathway-function coregulatory network was established and demonstrated that these hub genes were enriched in FoxO, TGF-β, Wnt, PIK3-Akt, MAPK, and cAMP signaling pathways, which play important roles in regulating cell apoptosis, cell proliferation, stress responses, and hormone secretion. The current research provides a comprehensive perspective of the effects of oxidative stress on porcine GCs and also identifies potential therapeutic targets for oxidative stress-induced female infertility.

Consequences of chemotherapeutic agents on primordial follicles and future clinical applications

The ovarian reserve is necessary for female fertility and endocrine health. Commonly used cancer therapies diminish the ovarian reserve, thus, resulting in primary ovarian insufficiency, which clinically presents as infertility and endocrine dysfunction. Prepubertal children who have undergone cancer therapies often experience delayed puberty or cannot initiate puberty and require endocrine support to maintain a normal life. Thus, developing an effective intervention to prevent loss of the ovarian reserve is an unmet need for these cancer patients. The selection of adjuvant therapies to protect the ovarian reserve against cancer therapies underlies the mechanism of loss of primordial follicles (PFs). Several theories have been proposed to explain the loss of PFs. The "burn out" theory postulates that chemotherapeutic agents activate dormant PFs through an activation pathway. Another theory posits that chemotherapeutic agents destroy PFs through an "apoptotic pathway" due to high sensitivity to DNA damage. However, the mechanisms causing loss of the ovarian reserve remains largely speculative. Here, we review current literature in this area and consider the mechanisms of how gonadotoxic therapies deplete PFs in the ovarian reserve.

Protective effect of gallic acid against cisplatin-induced ototoxicity in rats

Introduction

Cisplatin is an antineoplastic agent widely used in the treatment of a variety of cancers. Ototoxicity is one of the main side-effects restricting the use of cisplatin.

Objective

The purpose of this study was to investigate the protective efficacy of gallic acid, in biochemical, functional and histopathological terms, against ototoxicity induced by cisplatin.

Methods

Twenty-eight female Sprague Dawley rats were included. Rats were randomly assigned into four groups of seven animals each. Cisplatin group received a single intraperitoneal dose of 15 mg/kg cisplatin. Gallic acid group received intraperitoneal gallic acid at 100 mg/kg for five consecutive days. Cisplatin + gallic acid group received intraperitoneal gallic acid at 100 mg/kg for five consecutive days and a single intraperitoneal dose of 15 mg/kg cisplatin at 3rd day. A control group received 1 mL intraperitoneal saline solution for five consecutive days. Prior to drug administration, all rats were exposed to the distortion product otoacoustic emissions test. The test was repeated on the 6th day of the study. All rats were then sacrificed; the cochleas were removed and set aside for biochemical and histopathological analyses.

Results

In cisplatin group, Day 6 signal noise ratio values were significantly lower than those of the other groups. Also, malondialdehyde levels in cochlear tissues were significantly higher, superoxide dismutase and glutathione peroxidase activities were significantly lower compared to the control group. Histopathologic evaluation revealed erosion in the stria vascularis, degeneration and edema in the connective tissue layer in endothelial cells, impairment of outer hair cells and a decrease in the number of these calls. In the cisplatin + gallic acid group, this biochemical, histopathological and functional changes were reversed.

Conclusion

In the light of our findings, we think that gallic acid may have played a protective role against cisplatin-induced ototoxicity in rats, as indicated by the distortion product otoacoustic emissions test results, biochemical findings and immunohistochemical analyses.