Evaluating the effects of betaine on testicular ischemia/reperfusion injury induced by torsion/detorsion in the rat.

In this research, the effects of betaine on testicular ischemia-reperfusion were evaluated. Forty rats were randomly divided into 4 groups of sham, torsion/detorsion (TD), torsion/detorsion with two different dosage of betaine 200 mg/kg, and 300 mg/kg, respectively. At the end of the experiment, the testosterone concentration, sperm motility, concentration and vitality, oxidative stress biomarkers including Malondialdehyde (MDA), Glutathione peroxidase (GPx), Catalase (CAT), and total antioxidant capacity (TAC) were assessed. Moreover, histopathological parameters including seminiferous tubules diameter (STD), seminiferous epithelium thickness (SET), spermatogonia nuclei diameter (SpND), Sertoli cell nuclei diameter (StND) and miotic index were evaluated. The testosterone concentration altered during torsion/detorsion and betaine could increase slightly the testosterone concentration after 15 days. Sperm motility and vitality significantly increased in the betaine treated groups compared to the TD group on days 3 and 15. Among oxidative stress biomarkers, only CAT on day 3 and GPx on day 15 were significantly higher in the betaine groups compared to the TD group. Among histopathological parameters an increase in the STD and SET in betaine-200 and betaine-300 groups were observed on 15th day of post-surgery, compared to the TD group. These findings indicate that betaine can ameliorate testicular damages triggered by torsion/detorsion.

Nitroglycerin ameliorates sperm parameters, oxidative stress and testicular injury following by testicular torsion/detorsion in male rats.

PURPOSE: This study was designed to determine the probable protection mechanisms of nitroglycerin, a widely used medication for treatment of heart failure and angina, in amelioration of testicular ischemia/reperfusion damage. METHODS: 24 adult male rats were randomly divided into three equal groups; with eight rats in each group: Group 1 (Sham) was sham-operated. Group 2 (T_D): 2 h testicular torsion was induced, afterward detorsion was performed and maintained for 2 h. Group 3 (NG): Nitroglycerin was administered immediately after detorsion. Sperm quality parameters such as viability, motility, morphology, and concentration, levels of antioxidant enzymes (glutathione peroxidase (GPX), catalase (CAT), and total antioxidant capacity (TAC)), and amount of malondialdehyde (MDA) in the blood plasma were examined in each group, thereafter histopathological parameters including germinal epithelial cell thickness (GECT), mean seminiferous tubular diameter (MSTD), Johnson's score and Cosentino's score were assessed. RESULTS: Testicular T_D significantly reduced sperm viability, motility, and normal morphology, whereas the NG administration remarkably increased the percentage of live, motile, and normal spermatozoa (p < 0.05). Levels of GPx, CAT, and TAC significantly reduced and the MDA level significantly increased in the T_D group in comparison to the sham group (p < 0.05). The NG treated group demonstrated significantly reduced MDA concentrations as well as elevated levels of GPx and CAT compared to the T_D group (p < 0.05). Induction of testicular torsion significantly reduced Johnson's score, GESCT (µm), and MSTD (µm), and remarkably increased the Cosentino's score (P < 0.05), while NG injection significantly increased Johnson's score, GESCT (µm), and MSTD (µm) and reduced the Cosentino's score (P < 0.05). CONCLUSION: According to the findings in this research, nitroglycerin was able to protect the testicular tissue from ischemia-reperfusion damage caused by induced torsion/detorsion.

Effect of royal jelly on testicular antioxidant enzymes activity, MDA level and spermatogenesis in rat experimental Varicocele model.

Varicocele is one of the most prevalent causes of infertility. It causes induction of oxidative stress, increases lipid peroxidation in the testis and disrupts spermatogenesis cycle. The aim of the study was to investigate the possible protective effects of royal jelly against varicocele induced oxidative stress, biochemical and histological alterations in the experimental varicocele model in rat. Twenty-one adult Wistar rats were divided into three groups. The control group (I), Varicocele and administration of normal saline (II), varicocele and treatment with RJ (III). At the end of the experiment, all the animals were sacrificed and testes excised. The activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and MDA levels were measured. Also, histopathological examinations, Johnsen scores and sperm parameters were determined. There was a significant (p<0.05) increase in the activity level of CAT (0.223±0.005), SOD (0.177±0.0062), GPx (9.575±0.318) and a significant (p<0.05) reduction in the MDA level (2.674±0.336) of the experimental varicocele treated with royal jelly when compared to the activity of CAT (0.011±0.004), SOD (0.035±0.0096), GPx (8.864±0.397) and MDA level (4.630±0.579) of the experimental varicocele and administration of normal saline. Results of the Johnsen score showed a significant increase (p<0.05) in the mean score of the RJ group (7.94±1.5) when compared to the normal saline group (6.04±1.4). Therefore, RJ is a potential area for further studies and improving in spermatogenesis cycle after varicocele.

Effect of ghrelin on the biochemical and histopathology parameters and spermatogenesis cycle following experimental varicocele in rat.

BACKGROUND: Varicocele is one of the major causes of infertility in men in which testicular function is progressively damaged. OBJECTIVES: This study aimed to determine the effect of ghrelin on antioxidant enzymes activity (catalase, SOD, GPx), malondialdehyde (MDA) level and spermatogenesis cycle after induction of varicocele in rat. MATERIALS AND METHODS: Twenty-one male Wistar rats were randomly divided into three groups: I-control group, II-rats with induced varicocele and injection of physiological saline and III-rats with induced varicocele and injection of ghrelin. At the end of the experiment, animals were sacrificed and their testes were removed. Antioxidant enzymes activity and MDA level were measured. Histopathological tests, Johnsen's score and sperm parameters were also evaluated. RESULTS: In varicocele group with ghrelin administration (group III), the levels of SOD (0.183 ± 0.024), GPX (9.4250 ± 0.103) and TAC (2.79 ± 0.464) increased significantly (p < 0.05), while MDA (0.304 ± 0.004) level decreased significantly (p < 0.05) compared with varicocele and normal saline group (II). There was no significant difference in the activity of catalase between group III (0.122 ± 0.018) and group II (0.108 ± 0.018), although ghrelin improved catalase activity in group III compared to group II. Also, in group III, there were significant increases in the Johnsen's score (7.920), sperm count (70.29 ± 5.82) and sperm viability (87.14 ± 5.21) compared with group II (p < 0.05). CONCLUSION: Ghrelin can improve the capacity of antioxidant enzymes to reduce the oxidative stress caused by varicocele and reduce spermatogenesis cycle. Therefore, special attention should be paid to ghrelin in studies evaluating antioxidant compounds in varicocele.

The Impact of Oxidative Stress on Testicular Function and the Role of Antioxidants in Improving it: A Review.

Oxidative stress is an important factor for development of male infertility because of very high rate of cell division and mitochondrial oxygen consumption in testicular tissue as well as comparably higher levels of unsaturated fatty acids in this tissue than in other tissues. Moreover, the level of oxygen pressure is low due to the weakness of testicular artery; therefore, there is a severe cell competition for oxygen. Therefore, the testicular tissue and male reproductive system are particularly susceptible to oxidative stress. On the other hand, exposure to X-ray, toxins and chemicals found in the environment as well as specific physical conditions such as varicocele can exacerbate the oxidative stress and induce apoptosis of germ cells and subsequently spermatogenesis. However, under normal conditions, the body's capacity to produce antioxidants for inhibiting adverse effects of oxidative stress is affected by metabolic process and genetic structure. Besides that, environmental factors such as diet, pollutants, and chemicals can affect this capacity. Thus, the body's antioxidant system alone is not able to neutralize all free radicals and prevent harmful complications of oxidative stress. Therefore, use of antioxidants and development of antioxidant therapy can break down the oxidative chain reaction and play a very significant role in increasing the body's capacity to fight free radical-induced oxidative stress, and therefore improve the process of spermatogenesis.

The plant histaminase: a promising enzyme with antioxidant properties versus histamine release in isoprenaline-induced myocardial infarction in rats.

The present study was designed to evaluate possible protective effects of purified histaminase from Lathyrus sativus L. seedling on the myocardial injuries upon isoprenaline-induced myocardial infarction in rats. In this regard, blood histamine concentration, creatine kinase-MB (CK-MB) activity, antioxidant status, and histopathological changes of the hearts were measured. A total of 40 adult male Sprague-Dawley rats were divided into five equal groups and treated in the following order: control (normal saline), isoprenaline (isoproterenol 110 mg/kg BW), Isopren.-H1 (isoprenaline plus histaminase 80 U/kg BW), Isopren.-H2 (isoprenaline plus histaminase 120 U/kg BW), and Isopren.-H3 (isoprenaline plus histaminase 160 U/kg BW). Myocardial infarction was manifested by a significant elevation in the level of CK-MB and histopathological findings in isoprenaline group when compared to controls. In contrast, histaminase pretreatment at dose of 160 U/kg prevented isoprenaline-induced histamine release and significantly decreased CK-MB activity as well as histopathological changes in Isopren.-H3 group. A significant increase in the catalase (CAT) and superoxide dismutase (SOD) activities was also observed by histaminase treatment in Isopren.-H2 and Isopren.-H3 groups. Although the activity of glutathione peroxidase (GPx) increased significantly to suppress oxidative stress in isoprenaline group, it was not able to prevent lipid peroxidation (as shown by TBARS concentration) in the heart of rats. In conclusion, the plant-originated histaminase presented as a promising enzyme with antioxidant properties against histamine release and myocardial infarction in rats, and it seems be a suitable therapeutic agent for future clinical trials in humans.

The plant histaminase: a promising enzyme with antioxidant properties versus histamine release in isoprenaline-induced myocardial infarction in rats

The present study was designed to evaluate possible protective effects of purified histaminase from Lathyrus sativus L. seedling on the myocardial injuries upon isoprenaline-induced myocardial infarction in rats. In this regard, blood histamine concentration, creatine kinase-MB (CK-MB) activity, antioxidant status, and histopathological changes of the hearts were measured. A total of 40 adult male Sprague-Dawley rats were divided into five equal groups and treated in the following order: control (normal saline), isoprenaline (isoproterenol 110 mg/kg BW), Isopren.-H1 (isoprenaline plus histaminase 80 U/kg BW), Isopren.-H2 (isoprenaline plus histaminase 120 U/kg BW), and Isopren.-H3 (isoprenaline plus histaminase 160 U/kg BW). Myocardial infarction was manifested by a significant elevation in the level of CK-MB and histopathological findings in isoprenaline group when compared to controls. In contrast, histaminase pretreatment at dose of 160 U/kg prevented isoprenaline-induced histamine release and significantly decreased CK-MB activity as well as histopathological changes in Isopren.-H3 group. A significant increase in the catalase (CAT) and superoxide dismutase (SOD) activities was also observed by histaminase treatment in Isopren.-H2 and Isopren.-H3 groups. Although the activity of glutathione peroxidase (GPx) increased significantly to suppress oxidative stress in isoprenaline group, it was not able to prevent lipid peroxidation (as shown by TBARS concentration) in the heart of rats. In conclusion, the plant-originated histaminase presented as a promising enzyme with antioxidant properties against histamine release and myocardial infarction in rats, and it seems be a suitable therapeutic agent for future clinical trials in humans

Ghrelin is a suppressor of testicular damage following experimentally induced cryptorchidism in the rat.

BACKGROUND: Cryptorchidism is associated with increased level of reactive oxygen species and lipid peroxidation. This study was undertaken to examine the possible ghrelin ability in attenuation of testicular damage in response to elevated temperature. METHODS: Thirty male rats were subdivided into sham-operated, cryptorchidism-saline and cryptorchidism-ghrelin group. Bilateral cryptorchidism was induced in groups 2 and 3, surgically. The animals in group 3 were given ghrelin for 7 days and all testes were taken for biochemical and photomicrograph analysis. RESULTS: Glutathione peroxidase activity and glutathione content significantly promoted on day 7 in the cryptorchid rats treated by ghrelin. Catalase activity was higher in the ghrelin-exposed animals than the cryptorchidism-saline group on both experimental days. Although superoxide dismutase activity was elevated by ghrelin treatment on both days, it did not differ significantly. By contrast, significant reduction was observed in thiobarbituric acid reactive substances concentrations following ghrelin administration on day 7. Moreover, ghrelin could improve histopathological scores of the testes, and diminished formation of giant cells and tubular vacuolization. CONCLUSIONS: These findings indicate for the first time the novel evidence of ghrelin antioxidant properties in attenuation of rat testicular injury following experimentally induced cryptorchidism.

Oleuropein prevents ethanol-induced gastric ulcers via elevation of antioxidant enzyme activities in rats

Purified oleuropein from olive leaf extract has been shown to have antioxidant effects in our recent studies. Thus, the aim of this study was to assess the antioxidant abilities of oleuropein in comparison with ranitidine in ethanol-induced gastric damages via evaluation of ulcer index inhibition, antioxidant enzyme activities, and lipid peroxidation level. Fifty-six adult male Sprague-Dawley rats were divided into seven equal groups as follows: control group, ethanol group (absolute ethanol 1 ml/rat), oleuropein group (12 mg/kg), and oleuropein (6, 12, and 18 mg/kg) plus ethanol groups, as well as ranitidine (50 mg/kg) plus ethanol group. Pretreatment with oleuropein (12 and 18 mg/kg) significantly increased the ulcer index inhibition (percent), in comparison with oleuropein (6 mg/kg). Glutathione peroxidase (GPx) activity was significantly lower in the ethanol group when compared with the other groups whereas, treatment of rats with oleuropein (12 mg/kg) significantly increased glutathione content in gastric tissue when compared with the other groups, and lipid peroxidation was significantly reduced in the oleuropein- (12 and 18 mg/kg) and ranitidine-treated animals. Superoxide dismutase (SOD) and catalase (CAT) activities were both much higher in oleuropein-treated rats than the ethanol group, and although there was a moderate increase in SOD and CAT activities in ranitidine-treated rats, the differences were not significant. These findings suggest that oleuropein has beneficial antioxidant properties against ethanol-induced gastric damages in the rat. Therefore, it seems that a combination regimen including both antioxidant and antisecretory drugs may be beneficial in prevention of ethanol-mediated gastric mucosal damages (AU)

Ghrelin regulates Bax and PCNA but not Bcl-2 expressions following scrotal hyperthermia in the rat.

More recently, we have reported the beneficial effects of ghrelin in improvement of histopathological features of the rat testis following local heat exposure. However, the exact mechanism and the precise role of apoptosis- and proliferation-specific proteins in this regeneration process remained to be explored. Thus, thirty adult male Wistar rats were allotted for the experiment and subdivided equally into three groups: control-saline (CS), heat-saline (HS) and heat-ghrelin (HG). The scrota of HS and HG groups were immersed once in water bath at 43°C for 15 min. HG animals received 2 nmol of ghrelin subcutaneously immediately after heating every other day until day 60 and the other groups were given physiological saline using the same method. The testes of all groups were taken after rat killing on days 30 and 60 after heat treatment for immunocytochemical detection of pro-apoptotic factor Bax, anti-apoptotic protein Bcl-2 and proliferation-associated peptide PCNA in the germ cells. Ghrelin could significantly suppress the Bax expression in spermatocytes compared to the HS group at day 30 (P<0.05). Likewise, the mean percentages of spermatogonia containing Bax substance were lower in ghrelin-exposed animals, however the differences were not statistically significant. There were immunoreactive cells against Bcl-2 in each germ cell neither in the control nor in the heated animals of experimental groups. In contrast, the number of PCNA immunolabeling cells were higher in HG group in compared to HS or CS animals on both experimental days (P<0.001). Down-regulation of Bax expression concurrent with overexpression of PCNA in HG group indicates the ability of ghrelin in acceleration of testicular germ cells regeneration following heat stress. These findings indicate that ghrelin may be used as a novel and efficient antioxidant agent to induce resumption of spermatogenesis upon environmental heat exposure.

Oleuropein prevents ethanol-induced gastric ulcers via elevation of antioxidant enzyme activities in rats.

Purified oleuropein from olive leaf extract has been shown to have antioxidant effects in our recent studies. Thus, the aim of this study was to assess the antioxidant abilities of oleuropein in comparison with ranitidine in ethanol-induced gastric damages via evaluation of ulcer index inhibition, antioxidant enzyme activities, and lipid peroxidation level. Fifty-six adult male Sprague-Dawley rats were divided into seven equal groups as follows: control group, ethanol group (absolute ethanol 1 ml/rat), oleuropein group (12 mg/kg), and oleuropein (6, 12, and 18 mg/kg) plus ethanol groups, as well as ranitidine (50 mg/kg) plus ethanol group. Pretreatment with oleuropein (12 and 18 mg/kg) significantly increased the ulcer index inhibition (percent), in comparison with oleuropein (6 mg/kg). Glutathione peroxidase (GPx) activity was significantly lower in the ethanol group when compared with the other groups whereas, treatment of rats with oleuropein (12 mg/kg) significantly increased glutathione content in gastric tissue when compared with the other groups, and lipid peroxidation was significantly reduced in the oleuropein- (12 and 18 mg/kg) and ranitidine-treated animals. Superoxide dismutase (SOD) and catalase (CAT) activities were both much higher in oleuropein-treated rats than the ethanol group, and although there was a moderate increase in SOD and CAT activities in ranitidine-treated rats, the differences were not significant. These findings suggest that oleuropein has beneficial antioxidant properties against ethanol-induced gastric damages in the rat. Therefore, it seems that a combination regimen including both antioxidant and antisecretory drugs may be beneficial in prevention of ethanol-mediated gastric mucosal damages.

The effect of ghrelin pretreatment on epididymal sperm quality and tissue antioxidant enzyme activities after testicular ischemia/reperfusion in rats

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Ghrelin, the endogenous ligand for growth hormone secretagogue receptor, has been reported to prevent ischemia/reperfusion (I/R) injury in various tissues by its antioxidant activity. Therefore, this study was aimed to investigate the effect of ghrelin on sperm quality and antioxidant enzyme activity in a rat testicular ischemia/reperfusion injury model. Forty-two male Wistar rats were divided into groups control, I/R, and I/R plus ghrelin. The right testes were rotated 720° for 1 h and were allowed to reperfuse for 4 h and 30 days thereafter. Ghrelin (40 nmol/kg IP) or vehicle (physiological saline) was administrated 15 min before reperfusion. After 4 h of reperfusion, a right orchiectomy was performed to measure the biochemical parameters. In addition, the sperm was collected from the epididymis after 30 days of reperfusion, and sperm characteristics were examined. The malondialdehyde levels of the testis tissues were significantly increased, but a statistically significant decrease was found in the superoxide dismutase, glutathione peroxidase, and catalase activities in the I/R group as compared with the control, indicating I/R injury. The sperm evaluation showed a significant reduction in all characteristics resulted from I/R compared with the control. In the ghrelin-treated group, the malondialdehyde values were significantly lowered, and only enzyme activity of glutathione peroxidase showed significant increases compared with the I/R group. Ghrelin significantly enhanced sperm motility, movement, and concentration but did not prevent I/R-induced reduction in membrane integrity in the testes of rats compared to the I/R group. Our results suggest that ghrelin treatment has a protective role on IR-induced testicular injury, and this effect may be due to its antioxidant properties (AU)

Ghrelin modulates testicular germ cells apoptosis and proliferation in adult normal rats.

Under normal condition in the most mammals, spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. The present study was designed to determine the effects of ghrelin treatment on in vivo quality and quantity expression of apoptosis and proliferation specific indices in rat testicular germ cells. Twenty eight adult normal rats were subdivided into equal control and treatment groups. Treatment group received 3 nmol of ghrelin as subcutaneous injection for 30 consecutive days or vehicle to the control animals. The rats from each group (n=7) were killed on days 10 and 30 and their testes were taken for immunocytochemical evaluation and caspase-3 assay. Immunohistochemical analysis indicated that the accumulations of Bax and PCNA peptides are generally more prominent in spermatocytes and spermatogonia of both groups. Likewise, the mean percentage of immunoreactive spermatocytes against Bax increased (P<0.01) in the ghrelin-treated group on day 10, while despite of 30% increment in the Bax level of spermatocytes in the treated rats on day 30, however, it was not statistically significant. During the experimental period, only a few spermatogonia represented Bax expression and the changes of Bax immunolabling cells were negligible upon ghrelin treatment. Likewise, there were immunostaining cells against Bcl-2 in each germ cell neither in the control nor in the treated animals. In fact, ghrelin balanced Bax/Bcl-2 ratio toward at increase of Bax level in the spermatocytes and therefore may stimulate apoptosis in these germ cells. In contrast, ghrelin administration significantly suppressed proliferation-associated peptide PCNA in the spermatocytes as well as spermatogonia (P<0.05). Whereas, caspase-3 activity did not show any marked alteration during the experiment in both groups (P>0.05). Upstream of Bax substance parallel to down-regulation of PCNA demonstrate that ghrelin may prevent massive accumulation of germ cells during normal spermatogenesis. These observations also indicate that ghrelin may be considered as a modulator of spermatogenesis in normal adult rats and could be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors.

The effect of ghrelin pretreatment on epididymal sperm quality and tissue antioxidant enzyme activities after testicular ischemia/reperfusion in rats.

Ghrelin, the endogenous ligand for growth hormone secretagogue receptor, has been reported to prevent ischemia/reperfusion (I/R) injury in various tissues by its antioxidant activity. Therefore, this study was aimed to investigate the effect of ghrelin on sperm quality and antioxidant enzyme activity in a rat testicular ischemia/reperfusion injury model. Forty-two male Wistar rats were divided into groups control, I/R, and I/R plus ghrelin. The right testes were rotated 720° for 1 h and were allowed to reperfuse for 4 h and 30 days thereafter. Ghrelin (40 nmol/kg IP) or vehicle (physiological saline) was administrated 15 min before reperfusion. After 4 h of reperfusion, a right orchiectomy was performed to measure the biochemical parameters. In addition, the sperm was collected from the epididymis after 30 days of reperfusion, and sperm characteristics were examined. The malondialdehyde levels of the testis tissues were significantly increased, but a statistically significant decrease was found in the superoxide dismutase, glutathione peroxidase, and catalase activities in the I/R group as compared with the control, indicating I/R injury. The sperm evaluation showed a significant reduction in all characteristics resulted from I/R compared with the control. In the ghrelin-treated group, the malondialdehyde values were significantly lowered, and only enzyme activity of glutathione peroxidase showed significant increases compared with the I/R group. Ghrelin significantly enhanced sperm motility, movement, and concentration but did not prevent I/R-induced reduction in membrane integrity in the testes of rats compared to the I/R group. Our results suggest that ghrelin treatment has a protective role on IR-induced testicular injury, and this effect may be due to its antioxidant properties.

Ghrelin attenuates heat-induced degenerative effects in the rat testis.

This study was conducted to examine the efficacy of ghrelin in prevention of deleterious effects of heat stress in rat testicular tissue. Forty five adult male rats were scheduled for this study and were divided equally into three groups: heat-saline, heat-ghrelin and control-saline. The scrota of heated-designed rats were immersed once in water bath at 43 °C for 15 min. Immediately upon heating, 2 nmol of ghrelin were given subcutaneously to heat-ghrelin animals every other day up to day 60 and physiological saline to the other two groups using the same method. The animals were sacrificed at 10, 30 and 60 days after heat treatment and their testes were taken for later photomicrograph and immunohistochemical analysis. Testicular histopathology revealed a significant reduction in the means of seminiferous tubules and Sertoli cell nucleus diameters as well as germinal epithelium height on day 10 in both heated groups. Furthermore, other testicular components including miotic index, spermatogenesis rate, presence of spermatocytes and volume densities were dramatically decreased following heat exposure. Notably, ghrelin caused a partial recovery in all of the above-mentioned parameters and accelerated testicular regeneration process by day 30 compared to the heat-saline group (P<0.05). Because of testicular progressive recovery, these indices were similar among groups on day 60 (P>0.05). However, immunohistochemistry evaluation for in situ detection of Bcl-2 protein did not exhibit any germ cells-positive of this factor among groups at different experimental days. In conclusion, the results of the present study indicate for the first time the novel evidences of ghrelin ability in attenuation of heat-induced testicular damage and also that ghrelin therapy may be useful as a suppressor of degenerative effects following testicular hyperthermia.

Ghrelin promotes antioxidant enzyme activity and reduces lipid peroxidation in the rat ovary.

Antioxidant properties of ghrelin have been recently reported on various oxidative stresses in limited tissues. This study was set to examine the possible antioxidative effects of ghrelin in rat ovarian tissue. Twenty eight female adult Wistar rats were randomly allocated into control and treatment groups. Treatment group (n=14) received 2nmol of ghrelin as subcutaneous injection for 14 consecutive days or vehicle (physiological saline) to the control rats. The animals from both groups were equally killed on days 9 and 14 after beginning of ghrelin injection (n=7 from each group on each day) and their ovaries were taken for later antioxidant enzyme activity assays as well as measurement of glutathione content and thiobarbituric acid reactive substances (TBARS) level. Superoxide dismutase activity was significantly higher on days 9 (P<0.05) and 14 (P<0.01) in the treated group compared to the control rats. By contrast, lipid peroxidation, as TBARS value, reduced significantly on both experimental days in the ghrelin-exposed animals (P<0.05). Although, the mean activity of catalase and glutathione content was greater in the treated rats, however, the differences were not statistically significant. Slight changes occurred in glutathione peroxidase activity during the experimental period and there were no differences either on day 9 or on day 14 between groups. In conclusion, the results of the present investigation indicate for the first time the novel evidence of antioxidant properties of ghrelin in the rat ovary.