Zinc acetate pretreatment ameliorates cisplatin-induced Sertoli cell dysfunction in Sprague-Dawley rats

Alpha-pinene neutralizes cisplatin-induced reproductive toxicity in male rats through activation of Nrf2 pathway

PURPOSE

Testicular toxicity is one of the most important side effects of cisplatin (CP) therapy. Alpha-pinene (AP) is a naturally occurring monoterpene with antioxidant character in plants. Here, we aimed to evaluate the therapeutic activity of AP against CP-induced testicular toxicity by including the nuclear factor erythroid 2-associated factor 2 (Nrf2) pathway in rats.

METHODS

Thirty male rats were divided into 5 groups: control, CP, CP + AP (5 and 10 mg/kg) and only AP (10 mg/kg). CP was administered intraperitoneally at a dose of 5 mg/kg on the first day, followed by three consecutive injections of AP. Serum reproductive hormone levels were evaluated using ELISA kits. Oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in testicular tissue were also determined colorimetrically. In addition, how CP affects Nrf2 pathway and the effect of AP on this situation were also addressed.

RESULTS

Treatment with CP significantly increased OS, inflammation, ERS and apoptosis in testicular tissue. Administrations of AP resulted in an amelioration of these altered parameters. The mechanism of therapeutic effect of AP appeared to involve induction of Nrf2. Furthermore, these results were also confirmed by histological data.

CONCLUSION

Results suggest that AP can exhibit therapeutic effects against CP-induced testicular toxicity. It can be concluded that AP may be a potential molecule to abolish reproductive toxicity after chemotherapy.

Cisplatin-induced genotoxic effects and endogenous glutathione levels in mice bearing ascites Dalton's lymphoma

cis-Diaminedichloroplatinum(II), commonly known as cisplatin, treatment of mice for 24-96, 30 h and 10 days caused the development of chromosomal aberrations in bone marrow cells as well as in Dalton's lymphoma (DL) cells, micronuclei (MN) in bone marrow cells and abnormalities in sperm heads, and it indicates the genotoxic potential of cisplatin in the host. Cisplatin exerts differential effects on the chromosomes of the bone marrow and tumor cells. Combination treatment of cisplatin with L-buthionine(S,R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, enhanced these cisplatin-induced genotoxic effects, but supplementing glutathione level with cysteine, its precursor, reduced the cisplatin-induced genotoxicity. The reduction in cellular glutathione level may facilitate increased intracellular accumulation and binding of drug to DNA to enhance the frequency of genotoxicity parameters. These findings support the possible involvement of glutathione as an important intracellular protective agent and suggest that differences in its levels may be one of the factors in the varying sensitivity of cells to cisplatin-induced genotoxic effects in the mice bearing ascites Dalton's lymphoma.

Vitamin C mediated protection on cisplatin induced mutagenicity in mice

In present studies the development of chromosomal aberrations, micronuclei in bone marrow cells and sperm head abnormalities were used as mutagenic bioassay in Swiss albino mice treated with cisplatin alone or ascorbic plus cisplatin. It was noted that in the combined treated hosts the frequency of all the mutagenic parameters were always significantly less than that treated with cisplatin alone. These findings suggest a protective role of ascorbic acid against cisplatin induced mutagenic potentials. Interestingly, in combined treated hosts glutathione (GSH) level in bone marrow cells increased significantly which may suggest a possible mechanism of ascorbic acid mediated protection against cisplatin induced mutagenic potentials in the hosts.

Metallothionein and anticancer agents: the role of metallothionein in cancer chemotherapy

Metallothioneins (MTs) are intracellular proteins containing the highest amount of thiol groups within the cytoplasm. These thiol groups are able to bind several cytotoxic agents, such as platinum compounds and alkylating agents. Increased levels of MT are one mechanism of resistance to these anticancer drugs, as intracytoplasmic binding of MT prevents the active molecules from reaching their target, the intranuclear DNA of tumor cells. MT synthesis can easily be induced by physiologic heavy metals such as zinc and copper. Pharmacological modulation of MT levels has been used to increase the MT pool in normal tissues and decrease their susceptibility to the toxicity of anticancer drugs. In the case of tumors arising in the brain, where the inducibility of MT synthesis is low, this approach would allow protection of normal tissues without decreasing the antitumor activity of the cytotoxic agents. The interaction of MT with cytotoxic agents is not limited to covalent binding. A correlation between MT synthesis and amplification of oncogenes such as ras has been reported. Furthermore, the cytotoxic drugs are bound by MT after competition with zinc and copper; these metals are cofactors of numerous metalloenzymes, some of which are involved in the metabolism of nucleic acids. Competitive displacement of these metals might modify nucleic acid metabolism and influence cellular proliferation. On the other hand, increased MT levels could provide a zinc cofactor reserve that increases the cell's reparative potential when faced by DNA damage by cytotoxic agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of carboplatin on the testis. A histological study

In the present study, the influence of carboplatin [diammine(cyclobutane-1,1-dicarboxylato)platinum(II)], the main and most active representative of second-generation antitumour platinum complexes, on the morphology of the testes of male CF1 mice was investigated histologically by examining semithick sections. Carboplatin was administered in doses of 30, 60, or 120 mg/kg and applied as a single intraperitoneal injection. For comparison purposes, the parent compound cisplatin [cis-diamminedichloroplatinum(II)] was administered at equitoxic doses (3, 6 or 12 mg/kg). At various intervals between days 1 and 28 after treatment, the testes were removed and embedded in Epon. Both compounds effected severe structural alterations of Sertoli cells, disrupted the blood/testis barrier, and impaired the processes both of spermatogenesis and spermiohistogenesis. The structural damage in the testes following treatment with carboplatin was at least as pronounced as that occurring under the influence of equitoxic doses of cisplatin. Within a few days, the intercellular spaces around Sertoli cells widened, the tight contacts with neighbouring cells were disrupted, the cytoplasm of Sertoli cells disintegrated and their nuclei shrank. Numerous necroses, abnormal mitotic figures of spermatogenic cells and malformed spermatozoa appeared. Severe damage was evident on days 10-21 after treatment with carboplatin, the strength of the symptoms being clearly dependent on the dose applied. The first indications of ongoing recovery processes were detected on day 21 in the case of the low dose (30 mg/kg) or on day 28 following treatment with 60 mg/kg or 120 mg/kg. These results confirm that carboplatin is at least as toxic to the testes as cisplatin and that its substitution for cisplatin in clinical therapy does not diminish the problem of drug-induced infertility following platinum-based chemotherapy.