4-Methylthiobenzoic acid reduces cisplatin nephrotoxicity in rats without compromising anti-tumour activity

Phenolic Acids (Gallic and Tannic Acids) Modulate Antioxidant Status and Cisplatin Induced Nephrotoxicity in Rats

Cisplatin (cis-diamminedichloroplatinum (II) or CDDP), used in the treatment of many solid-tissue cancers, has its chief side-effect in nephrotoxicity. Hence, this study sought to investigate and compare the protective effect of gallic acid (GA) and tannic acid (TA) against cisplatin induced nephrotoxicity in rats. The rats were given a prophylactic treatment of GA and TA orally at a dose of 20 and 40 mg/kg body weight for 7 consecutive days before the administration of a single intraperitoneal (i.p.) injection of cisplatin (CP) at 7.5 mg/kg bwt. The protective effects of both GA and TA on CP induced nephrotoxicity were investigated by assaying renal function, oxidative stress biomarkers, and histopathological examination of kidney architecture. A single dose of cisplatin (7.5 mg/kg bwt) injected i.p. caused a significant increase in some biomarkers of renal function (creatinine, uric acid, and urea levels), with a marked elevation in malondialdehyde (MDA) content accompanied by a significant (P < 0.05) decrease in reduced glutathione (GSH) content (103.27%) of kidney tissue as compared to control group. Furthermore, a significant (P < 0.05) reduction in kidney antioxidant enzymes (SOD, catalase, GPx, and GST) activity was observed. However, pretreatment with oral administration of tannic acid and gallic acid at a dose of 20 and 40 mg/kg body weight, respectively, for 7 days prior to cisplatin administration reduced histological renal damage and suppressed the generation of ROS, lipid peroxidation, and oxidative stress in kidney tissues. These results indicate that both gallic and tannic acids could serve as a preventive strategy against cisplatin induced nephrotoxicity.

Cisplatin otoprotection using transtympanic L-N-acetylcysteine: a pilot randomized study in head and neck cancer patients

OBJECTIVES/HYPOTHESIS

To evaluate the feasibility and efficacy of transtympanic L-N-Acetylcysteine (L-NAC) administration in patients receiving cisplatin chemotherapy for head and neck cancer.

STUDY DESIGN

Prospective randomized nonblinded open-label clinical trial.

METHODS

Transtympanic 2% L-NAC was administered to one randomly selected ear with the other ear as control in each patient. Primary outcome parameter was the difference in the loss of pure tone averages (PTA) at 2, 4, and 8 kHz between the L-NAC and control ear at 1 to 2 months following chemotherapy.

RESULTS

Eleven patients completed the study, with two patients demonstrating significantly better hearing in the L-NAC treated ear (18.2%). However, for the overall group, the difference in hearing preservation did not reach significance. Two percent L-NAC administration was well tolerated in this patient population. There were no adverse effects associated with L-NAC.

CONCLUSION

Although the study did not demonstrate a significant benefit overall, transtympanic L-NAC was associated with significantly better hearing in two patients. Better delivery methods may improve the efficacy of this treatment. L-NAC remains a promising drug in preventing cisplatin-induced ototoxicity.

Chrysin protects against cisplatin-induced colon. toxicity via amelioration of oxidative stress and apoptosis: probable role of p38MAPK and p53

Cisplatin, an antineoplastic drug, is widely used as a foremost therapy against numerous forms of cancer but it has pronounced adverse effects viz., nephrotoxicity, ototoxicity etc. CDDP-induced emesis and diarrhea are also marked toxicities that may be due to intestinal injury. Chrysin (5,7-dihydroxyflavone), a natural flavone commonly found in many plants possesses multiple biological activities, such as antioxidant, anti-inflammatory and anti-cancer effects. In the present study, we investigated the protective effect of chrysin against CDDP-induced colon toxicity. The plausible mechanism of CDDP-induced colon toxicity and damage includes oxidative stress, activation of p38MAPK and p53, and colonic epithelial cell apoptosis via upregulating the expression of Bak and cleaved caspase-3. Chrysin was administered to Wistar rats once daily for 14 consecutive days at the doses of 25 and 50 mg/kg body weight orally in corn oil. On day 14, a single intraperitoneal injection of cisplatin was given at the dose of 7.5 mg/kg body weight and animals were euthanized after 24 h of cisplatin injection. Chrysin ameliorated CDDP-induced lipid peroxidation, xanthine oxidase activity, glutathione depletion, decrease in antioxidant (catalase, glutathione reductase, glutathione peroxidase and glucose-6 phosphate dehydrogenase) and phase-II detoxifying (glutathione-S-transferase and quinone reductase) enzyme activities. Chrysin also attenuated goblet cell disintegration, expression of phospho-p38MAPK and p53, and apoptotic tissue damage which were induced by CDDP. Histological findings further supported the protective effects of chrysin against CDDP-induced colonic damage. The results of the present study suggest that the protective effect of chrysin against CDDP-induced colon toxicity was related with attenuation of oxidative stress, activation of p38MAPK and p53, and apoptotic tissue damage.

Amelioration of cisplatin-induced nephrotoxicity by extracts of Hemidesmus indicus and Acorus calamus

Administration of commonly used anticancer drug cisplatin [cis-diamminedichloroplatinum (II)] at pharmacologically relevant concentrations (12 mg/kg body weight) resulted in severe renal toxicity as evidenced from histopathological observations and biochemical alterations in the renal tissue. The extracts of medicinal plants Hemidesmus indicus L. (Apocynaceae) and Acorus calamus L. (Araceae) protected the renal tissue effectively from cisplatin-induced toxicity. Treatment of cisplatin-administered animals with the plant extracts could prevent the drug-induced oxidative damage in the renal tissue as evidenced from the decreased levels of lipid peroxidation and enhanced activities of the antioxidants in the renal tissue. Cisplatin treatment increased serum urea level to 41.3 +/- 2.86 mg/dL and administration of the extracts of H. indicus and A. calamus brought down the level to 34.54 +/- 0.37 and 30.12 +/- 0.95 mg/dL, respectively. Serum creatinine levels were increased to 1.1 +/- 0.02 mg/dL following cisplatin administration, and treatment with extracts of H. indicus and A. calamus brought this down to 0.76 +/- 0.09 and 0.61 +/- 0.06 mg/dL, respectively. The histopathological observations indicated that treatment with the H. indicus and A. calamus extracts restored the cisplatin-induced structural alterations in the renal tissue.

Co-supplementation of single and multi doses of vitamins C and E ameliorates cisplatin-induced acute renal failure in mice

Higher doses of antioxidant vitamins C and E have been proved to be effective against cisplatin-induced nephrotoxicity in animals. However, the possible effective equivalent dose in human was found to be higher than that of the upper tolerable intake level (UL) for these vitamins. Hence, the current study was aimed to evaluate the protective effect of co-supplementation of single and multi doses of vitamins C and E against cisplatin-induced acute renal failure in mice. Single dose of vitamin C (500 mg/kg), vitamin E (500 mg/kg), and vitamin C plus vitamin E (250 mg/kg each) were administered orally 1 h prior to cisplatin (12 mg/kg, i.p) injection, whereas in a multidose study they were administered 1 h prior, and 24 and 48 h after the cisplatin injection. Serum urea and creatinine levels were estimated 72 h after the injection of cisplatin. Renal concentrations of glutathione (GSH) and malondialdehyde (MDA) were also determined. Co-supplementation of vitamins significantly protected the cisplatin-induced increased levels of serum urea, creatinine, renal MDA, and the declined renal GSH level. Administration of single and multi doses of vitamin C plus E (250 mg/kg each) rendered significant nephroprotection. Therefore, accounting for the rare side effect from high intake of vitamins C and E observation of this study indicates that a multidose combination therapy of these vitamins at their lower doses can be effective in protecting the cisplatin-induced renal damage. The protection is partially mediated through the antioxidant effect of the vitamins.

Enhanced antitumor efficacy of cisplatin in combination with HemoHIM in tumor-bearing mice

Background

Although cisplatin is one of the most effective chemotherapeutic agents, cisplatin alone does not achieve a satisfactory therapeutic outcome. Also cisplatin accumulation shows toxicity to normal tissues. In this study, we examined the possibility of HemoHIM both to enhance anticancer effect with cisplatin and to reduce the side effects of cisplatin in melanoma-bearing mice.

Methods

HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of 3 edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Anticancer effects of HemoHIM with cisplatin were evaluated in melanoma-bearing mice. We used a Cr⁵¹-release assay to measure the activity of NK/Tc cell and ELISA to evaluate the production of cytokines.

Results

In melanoma-bearing mice, cisplatin (4 mg/kg B.W.) reduced the size and weight of the solid tumors, and HemoHIM supplementation with cisplatin enhanced the decrease of both the tumor size (p < 0.1) and weight (p < 0.1). HemoHIM itself did not inhibit melanoma cell growth in vitro, and did not disturb the effects of cisplatin in vitro. However HemoHIM administration enhanced both NK cell and Tc cell activity in mice. Interestingly, HemoHIM increased the proportion of NK cells in the spleen. In melanoma-bearing mice treated with cisplatin, HemoHIM administration also increased the activity of NK cells and Tc cells and the IL-2 and IFN-γ secretion from splenocytes, which seemed to contribute to the enhanced efficacy of cisplatin by HemoHIM. Also, HemoHIM reduced nephrotoxicity as seen by tubular cell of kidney destruction.

Conclusion

HemoHIM may be a beneficial supplement during cisplatin chemotherapy for enhancing the anti-tumor efficacy and reducing the toxicity of cisplatin.

Zingiber officinale Roscoe alone and in combination with alpha-tocopherol protect the kidney against cisplatin-induced acute renal failure

Oxidative stress due to abnormal production of reactive oxygen molecules (ROM) is believed to be involved in the etiology of toxicities of many xenobiotics. Evidences suggested that ROM is involved in the nephrotoxicity of a widely used synthetic anticancer drug cisplatin. The nephroprotective effects of ethanol extract of Zingiber officinale alone and in combination with vitamin E (alpha-tocopherol) were evaluated using cisplatin (single dose of 10 mg/kg body wt, i.p) induced acute renal damage in mice. The results of the study indicated that Z. officinale significantly and dose dependently protected the nephrotoxicity induced by cisplatin. The serum urea and creatinine levels in the cisplatin alone treated group were significantly elevated (P<0.01) with respect to normal group of animals. The levels were reduced in the Z. officinale (250 and 500 mg/kg, p.o) plus cisplatin, vitamin E (250 mg/kg) plus cisplatin, and Z. officinale (250 mg/kg) with vitamin E plus vitamin E treated groups. The renal antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and level of reduced glutathione (GSH) were declined; level of malondialdehyde (MDA) was elevated in the cisplatin alone treated group. The activities of SOD, CAT GPx and level of GSH were elevated and level of MDA declined significantly (P<0.05) in the Z. officinale (250 and 500 mg/kg) plus cisplatin and Z. officinale (250 mg/kg) with vitamin E plus cisplatin treated groups. The protective effect of Z. officinale (250 mg/kg body wt) was found to be better than that of vitamin E (250 mg/kg body wt). The results also demonstrated that combination of Z. officinale (250 mg/kg) with vitamin E (250 mg/kg) showed a better protection compared to their 250 mg/kg alone treated groups. This study concluded that ethanol extract of Z. officinale alone and in combination with vitamin E partially ameliorated cisplatin-induced nephrotoxicity. This protection is mediated either by preventing the cisplatin-induced decline of renal antioxidant defense system or by their direct free radical scavenging activity.

Ascorbic acid and alpha-tocopherol protect anticancer drug cisplatin induced nephrotoxicity in mice: a comparative study

BACKGROUND

Oxidative stress, resulting from an imbalance between prooxidant and antioxidant systems in favor of the former, largely contributes to immune system deregulation and complications observed in end-stage renal disease (ESRD) and patients treated with hemodialysis. Reactive oxygen species and free radicals are involved in the nephrotoxicity induced by a synthetic anticancer drug cisplatin.

METHODS

A comparative study on the nephroprotective effects of antioxidant vitamins (250 and 500 mg/kg, p.o.), vitamin C (ascorbic acid) and vitamin E (alpha-tocopherol), was evaluated using cisplatin (10 mg/kg body wt, i.p.) induced oxidative renal damage in mice. Urea and creatinine in serum were estimated for the renal function. Antioxidant status was estimated in kidney homogenate.

RESULTS

We found that both vitamins at 500 mg/kg significantly (P<0.01) protected the nephrotoxicity induced by cisplatin. The cisplatin induced increase of urea and creatinine concentrations were reduced in the vitamins plus cisplatin (250 and 500 mg/kg, p.o.)-treated groups. However the cisplatin induced decline of renal antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities were increased only in the 500 mg/kg vitamins treated groups. Both vitamins at 250 and 500 mg/kg could increase the concentration of reduced glutathione (GSH) and protected the increase of cisplatin induced lipid peroxidation.

CONCLUSIONS

Higher doses of vitamins are effective to protect oxidative renal damage and vitamin C is the better nephroprotective agent than vitamin E. The protection is mediated partially by preventing the decline of renal antioxidant status.

Acceleration of cisplatin ototoxicity by perilymphatic application of 4-methylthiobenzoic acid

The antitumor agent cisplatin has dose-limiting side effects such as ototoxicity. Systemical co-treatment with anti-oxidants like 4-methylthiobenzoic acid (MTBA) and sodium thiosulfate (STS) provides protection against cisplatin ototoxicity. However, systemically administered protective agents may reduce the chemotherapeutic effect of cisplatin. Local application of the protective agents could avoid this undesirable effect. In the present study, we aimed at suppressing cisplatin-induced ototoxicity in guinea pigs by administering MTBA or STS perilymphatically through cochlear perfusion. Guinea pig cochleas were perfused for 10 min with artificial perilymph (ArtP) containing cisplatin at 0.3 mg/ml, either alone, or in combination with MTBA (0.1 or 1.0 mg/ml) or STS (0.75 or 3.0 mg/ml). The compound action potential (CAP) and the summating potential (SP), evoked by 8 kHz tone bursts, and the endocochlear potential (EP; MTBA only) were measured just before and 1, 2, 3 and 4 h after perfusion. Cisplatin gradually reduced the CAP amplitude in time. Adding MTBA only accelerated this ototoxic effect. After cisplatin treatment a decline was found in the EP, irrespective of co-treatment, i.e., addition of MTBA did not accelerate the EP decrease. In contrast to MTBA, STS ameliorated the ototoxic effect of cisplatin. In conclusion, local application of anti-oxidants can ameliorate cisplatin ototoxicity but this is not a feature of all anti-oxidants.

Application of antioxidants and other agents to prevent cisplatin ototoxicity

OBJECTIVE/HYPOTHESIS

To review the recent data from experiments performed in this laboratory to test the hypothesis that cisplatin ototoxicity is related to depletion of glutathione and antioxidant enzymes in the cochlea and that the use of antioxidants or protective agents would protect the cochlea against cisplatin damage and prevent hearing loss.

STUDY DESIGN/METHODS

Data were reviewed from experiments performed in this laboratory. Control rats were treated intraperitoneally with cisplatin 16 mg/kg. Experimental rats were given cisplatin in combination with one of the following protective agents: diethyldithiocarbamate, 4-methylthiobenzoic acid, ebselen, or lipoic acid. Animals in each group underwent auditory brainstem response (ABR) threshold testing before and 3 days after treatment. Cochleae were removed after final ABR testing and analyzed for glutathione and activities of the enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and malondialdehyde.

RESULTS

Rats in the control group receiving cisplatin were found to have significant ABR threshold shifts. This was accompanied by a reduction of glutathione and the activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase) and an elevation of malondialdehyde. Experimental animals had preservation of ABR thresholds and levels of glutathione, antioxidant enzyme activity, and malondialdehyde that were similar to untreated animals.

CONCLUSION

Cisplatin ototoxicity appears to be initiated by fee-radical production, which causes depletion of glutathione and antioxidant enzymes in the cochlea, and lipid peroxidation, manifested by an increase in malondialdehyde. These effects were blocked by each of a series of antioxidant compounds given in combination with cisplatin. A mechanism for cisplatin ototoxicity is elaborated with a proposed plan of chemoprevention using agents with different mechanisms of action. These substances could be used alone or in combination to reduce the severity of cisplatin ototoxicity in patients.

Effect of 4-methylthiobenzoic acid on cisplatin-induced ototoxicity in the rat

The purpose of this study was to investigate the effectiveness of 4-methylthiobenzoic acid (MTBA) as a protection agent against cisplatin (CDDP)-induced changes in organ of Corti surface structure, compared to electrophysiological changes. Electrophysiological change was assessed using auditory brainstem response (ABR) and morphological changes were assessed using scanning electron microscopy (SEM). Male Wistar rats underwent pre-treatment ABRs in response to clicks, and tone bursts at 2, 4, 8, 16, and 32 kHz. The three groups of rats were injected as follows: (1) MTBA (250 mg/kg, i.p.), (2) CDDP (16 mg/kg, i.p.), (3) CDDP+MTBA (16 mg/kg, i.p. + 250 mg/kg, i.p.). Post-treatment ABRs were performed 3 days after drug administration and rats were sacrificed. Their cochleae were harvested and SEM was used to examine the surface of the organ of Corti, specifically the number of inner hair cells (IHCs) and outer hair cells (OHCs) in the apical, middle and basal turns of the cochlea. Animal weight was measured on the first and final days. There was a good correlation between ABR threshold changes and hair cell loss in the high frequency region of the cochlea (basal turn), while threshold changes in the lower test frequencies (middle turn) appeared to be the result of more subtle changes in the cochlea. MTBA provided effective protection against cisplatin-induced ABR threshold changes at all test frequencies as well as hair cell loss. MTBA also protected against body weight loss.

Protection by ebselen against cisplatin-induced nephrotoxicity: antioxidant system

This study was designed to investigate the cisplatin-induced alteration in renal antioxidant system and the nephroprotection with ebselen. Male Wistar rats were injected with (1) vehicle control; (2) cisplatin; (3) ebselen; and (4) cisplatin plus ebselen. Rats were sacrificed three days post-treatment and plasma as well as kidney were isolated and analyzed. Plasma creatinine increased 598% following cisplatin administration alone which decreased by 158% with ebselen pretreatment. Cisplatin-treated rats showed a depletion of renal glutathione (GSH) levels (52% of control), while cisplatin plus ebselen injected rats had GSH values close to the controls. Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities decreased 38, 75 and 62% of control, respectively, and malondialdehyde (MDA) levels increased 174% of control following cisplatin administration, which were restored to control levels after ebselen treatment. The renal platinum level did not significantly change with ebselen pretreatment. This study suggests that the protection offered by ebselen against cisplatin-induced nephrotoxicity is partly related to the sparing of antioxidant system.

Protection by 4-methylthiobenzoic acid against cisplatin-induced ototoxicity: antioxidant system

This study was undertaken in order to determine the changes in auditory brainstem-evoked responses relationship with the changes in the levels of GSH, lipid peroxidation and antioxidant enzymes activity in cisplatin-induced ototoxicity and otoprotection by 4-methylthiobenzoic acid (MTBA). Male Wistar rats in different groups were treated as follows: 1) saline control; 2) cisplatin (16 mg/kg, intraperitoneally); 3) MTBA (250 mg/kg, intraperitoneally), and 4) cisplatin plus MTBA. Post-treatment auditory brainstem-evoked responses were performed after three days and the rats were sacrificed and cochleae harvested. The cochleae were analyzed for glutathione (GSH), antioxidant enzyme activity, and malondialdehyde levels. The cisplatin injected rats showed a threshold elevation of 31.9 +/- 16.0 dB above the pretreatment thresholds using click stimulus. Rats treated with MTBA plus cisplatin did not show significant elevation of hearing threshold. Cisplatin plus MTBA administration showed a higher levels of cochlear GSH (5.59 +/- 0.35 nmoles/mg protein) compared to cisplatin alone (4.46 +/- 0.13 nmoles/mg protein). Cisplatin treated rats showed a decrease in superoxide dismutase, catalase, glutathione peroxidase (GSH-peroxidase), and glutathione reductase (GSH-reductase) activities (57%, 83%, 78% and 58% of control). Cochlear superoxide dismutase, catalase and GSH-reductase activities and MDA levels were restored in the rats injected with cisplatin plus MTBA, compared to cisplatin alone. It is concluded that the protection conferred by MTBA against cisplatin ototoxicity is associated with sparing of the cochlear antioxidant system.

Variable efficacy of radical scavengers and iron chelators to attenuate gentamicin ototoxicity in guinea pig in vivo

Recent studies from our laboratory have suggested that the ototoxic side effects of gentamicin are caused by a metabolized or 'activated' from the drug. Furthermore, we have postulated that the activation proceeds via the formation of an iron-gentamicin complex and that this complex produces free radicals. The present study assessed the protection effects of free radical scavengers and iron chelators on gentamicin-induced ototoxicity in guinea pigs in vivo. Gentamicin (120 mg/kg per day for 19 days) caused progressive threshold shifts reaching 50-65 dB at 18 kHz. Co-therapy with different radical scavengers yielded results ranging from no protection (with allopurinol, dimethyl sulfoxide, benzoate, lazaroid U74389G) to a moderate attenuation of hearing loss (with mannitol, 4-methylthiobenzoate, WR-2721). This finding agrees well with previous reports of inconsistent effects of scavengers on aminoglycoside-induced ototoxicity although it should be cautioned that only a single dose and route of application was tested. Two iron chelators, deferoxamine and 2,3-dihydroxybenzoate, significantly reduced the gentamicin-induced threshold shifts to about 10 dB or less. Iron chelators markedly decreased total serum iron levels while gentamicin treatment alone had no influence. There were no differences in serum gentamicin levels among all treated groups. This study confirms that iron plays a critical role in gentamicin ototoxicity and suggests that iron chelators, which are well-established drugs in clinical therapy, may be promising therapeutic agents to reduce aminoglycoside ototoxicity.

Sulphhydryl-modifying reagents alter ototoxin block of muscarinic receptor-linked phosphoinositide turnover in the cochlea

In the 12-day-old rat cochlea, the synthesis of inositol phosphates (IPs) can be activated via M3 cholinoceptors. This stimulation is blocked by ototoxins (mercury, ethacrynate, cisplatin, neomycin), drugs with side effects that lead to damage of hair cells and strial cells. As these toxic effects can be reversed in vivo by thiol molecules, we investigated whether modifications of thiol compounds could be involved in ototoxin-induced inhibition of the IP turnover in the cochlea. For this purpose, we assessed whether the sulphhydryl-modifying reagents N-ethylmaleimide and cadmium modify the carbachol-stimulated formation of IPs in the 12-day-old rat cochlea. Both molecules inhibit the carbachol effect on a dose-dependent way without altering the basal metabolism of IPs. As cadmium may block some calcium channels, the effect of verapamil, another calcium channel antagonist, was tested. Verapamil (1-50 microM) does not alter carbachol-evoked IP formation, suggesting that the inhibitory effect of cadmium is not due to a calcium influx block. Binding experiments with the muscarinic ligand quinuclidinyl benzylate (QNB) showed that the sulphhydryl-modifying reagents do not displace QNB from binding sites. Combining ototoxins and reagents shows that N-ethylmaleimide acts synergistically with all ototoxins but ethacrynate while cadmium does so only with mercury. Both N-ethylmaleimide and cadmium have additive effects with ethacrynate. As a supplement, disulphide bond-modifying agents do not alter the carbachol-enhanced metabolism of IPs. These results suggest that molecules having thiol-modifying properties inhibit the carbachol-induced turnover of IPs without acting at the muscarinic sites.(ABSTRACT TRUNCATED AT 250 WORDS)