Defective sperm function is the most common cause of infertility, and until recently, was difficult to evaluate and treat. Mammalian spermatozoa membranes are rich in poly unsaturated fatty acids and are sensitive to oxygen induced damage mediated by lipid peroxidation. Hence, free radicals and reactive oxygen species [ROS] are associated with oxidative stress and are likely to play a number of significant and diverse roles in reproduction. The excessive generation of reactive oxygen species by abnormal spermatozoa and by contaminating leukocytes [leukocytospermia] has been identified as one of the few defined etiologies for male infertility. Moreover, environmental factors, such as pesticides, exogenous estrogens, and heavy metals may negatively impact spermatogenesis since male sperm counts were declined. In addition, aging is also likely to further induce oxidative stress. Limited endogenous mechanisms exist to reverse these damages. In a normal situation, the seminal plasma contains antioxidant mechanisms which are likely to quench these ROS and protect against any likely damage to spermatozoa. However, during genitourinary infection/inflammation these antioxidant mechanisms may downplay and create a situation called oxidative stress. Assessment of such oxidative stress status [OSS] may help in the medical treatment of male infertility by suitable antioxidants. The cellular damage in the semen is a result of an improper balance between ROS generation and scavenging activities. Therefore, numerous antioxidants such as vitamin C, vitamin E, glutathione, and coenzyme Q10, have proven beneficial effects in treating male infertility. A multi-faceted therapeutic approach to improve male fertility involves identifying harmful environmental and occupational risk factors, while correcting underlying nutritional imbalances to encourage optimal sperm production and function.

Thymoquinone (TQ) is the major active component of the volatile oil of Nigella sativa seeds. The effects of TQ on carbon tetrachloride (CC14)‐induced hepatotoxicity was investigated in male Swiss albino mice. Carbon tetrachloride (20 μl/Kg, i.p.) injected into mice, induced damage to liver cells and was followed by the increase in serum alanine aminotransferase (ALT) activity after 24 h. Oral administration of TQ in a single dose (100 mg/Kg) resulted in significant (p<0.001) protection against the hepatotoxic effects of CCl4. TQ was tested as a substrate for mice hepatic DT‐diaphorase in the presence of NADH. TQ appears to undergo reduction to dihydrothymoquinone (DHTQ). Reduction rates as a function of protein (liver homogenate) and substrate (TQ) concentrations are reported. An apparent Km of 0.1 mM and an apparent Vmax of 74 μmol/min/g liver were measured. TQ and DHTQ inhibited the in vitro non‐enzymatic lipid peroxidation in liver homogenate (induced by Fe3+‐ascorbate) in a dose dependent manner. In this in vitro model DHTQ was more potent in comparison with TQ and butylated hydroxytoluene (BHT). The IC50 for DHTQ, TQ and BHT were found to be 0.34, 0.87 and 0.58 μM respectively. The data suggest that the in vivo protective action of TQ against CCl4‐induced hepatotoxicity may be mediated through the combined antioxidant properties of TQ and its metabolite DHTQ.

It is well known that bone markers (e.g. osteocalcin and alkaline phosphatase) play a significant role in healing of bone fractures, whereas oxidative stress delay such healing. The present study aimed to investigate the effect of a mixture of antioxidants (vitamins A, C, E, and selenium) on oxidative stress parameters, and the levels of bone healing markers in the plasma of male patients following fixative surgery of long bones. Antioxidant tablets (300 µg vitamin A, 10 mg vitamin E, 60 mg vitamin C, and 75 µg selenium) were administered to groups 3 and 4 (10 patients in each) for 1 and 2 weeks, respectively, in addition to the regular postoperative treatment. Groups 1 (25 patients) and 2 (10 patients) received the regular post-operative treatment consisting of intravenous (I.V.) second generation of cephalosporin 1000 mg/day for 3 days, oral diclofenac 50 mg, and paracetamol 500 mg twice daily for 15 days. Osteocalcin level and alkaline phosphatase activity as well as antioxidant enzymes superoxide dismutase (SOD), glutathione reductase (GR), as well as glutathione (GSH), and thiobarbituric acid reactive substances (TBARS) as indices of oxidative stress, were determined in the plasma of all patients after 1 or 2 weeks of long-bone fixative surgery. The results revealed that osteocalcin level and the activity of alkaline phosphatase were markedly increased in the plasma of patients who received antioxidants for 2 weeks. In addition, after 1 and/or 2 weeks, the levels of TBARS were significantly lower in the antioxidant-treated patients compared with those who did not receive antioxidants. On the other hand, the activities of SOD and GR were markedly elevated in plasma of patients who received antioxidants after 1 or 2 weeks compared with patients who received regular therapy. Moreover, the level of plasma GSH was markedly increased only after 2 weeks in patients who received antioxidants. It is concluded that administration of antioxidant vitamins A, E, and C in addition to selenium could accelerate bone healing after long-bone fixative surgery. Therefore, antioxidants should be considered in designing therapeutic protocols in post-operative bone surgery.

The effect of L-histidinol (LHL) on the acute nephrotoxicity produced by cisplatin (CDDP; 6 mg/kg, i.v.) was investigated in the rat. Intraperitoneal administration of LHL (100 mg/kg × 5 doses, 2 h apart) starting 2 h prior to CDDP single injection produced significant protection of renal function. The attenuation of nephrotoxicity was evidenced by significant reductions in serum urea and creatinine concentrations, decreased polyuria, reduction in body weight loss, marked reduction in urinary fractional sodium excretion and glutathione-S-transferase (GST) activity, and increased urine/serum creatinine ratio as well as increased creatinine clearance. LHL significantly ameliorated the toxic renal biochemical changes induced by CDDP. Renal lipid peroxides, glutathione levels and GST activity showed a marked tendency towards the normal values. Accumulation of platinum in renal tissues was significantly decreased in the presence of LHL. It is concluded that LHL can act as a nephroprotectant, and it is suggested that it would have beneficial effects on the kidney in clinical settings.

The effect of feeding groups of mice with a diet containing 2000, 4000 and 6000 btg aluminum (A13*/g) for two weeks (subacute) or 2000 and 4000 gg A13+/g for eight weeks (subchronic) as well as the coadministration of vitamin E (c~tocopherol) 500 btJg with A13., on the status of glutathione (GSH) and lipid peroxides as thiobarbituric acid reactive substances (TBARS) in whole brain tissues were evaluated. Changes in TBARS were further evaluated in vitro following the incubation of brain homogenates of the A13+-fed mice in the presence of 50 gM FeSO4. The results of subacute experiments revealed that the brain levels of GSH were significantly decreased only in the group of mice that received 6000 gg Al3*/g diet (P<0.05) and this effect was partially ameliorated when vitamin E was coadministered with AI 3", TBARS were significantly increased in vitro only in the presence of free iron ions and depended on the concentration of A13" in the diet. The effect was opposed by the vitamin E intake. Following subchronic A13. intake, the GSH content of the brain was significantly decreased only in the group of mice that received 4000 gg A13-/g diet (P<0.01), while TBARS were significantly increased in the brain tissues in vivo as well as in the presence of free iron ions in vitro. However, coadminstration of vitamin E with A13" for eight weeks preserved GSH levels and decreased TBARS in the brain of mice in vivo and in the presence of free iron ions in vitro. It is concluded that the long term administration of vitamin E may prevent At3"-stimulated oxidative injury in the brain.

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