Persistent Renal Oxidative Stress Despite Mannitol Nephroprotection: The Impact of Social-Single Prolonged Stress in Male and Female Rats Exposed to Cisplatin

Abstract

Cisplatin (CIS) is a chemotherapeutic agent known for nephrotoxicity through oxidative stress. Cancer treatment is also associated with psychological stress. Repeated exposure to social-single prolonged stress (social-SPS) modulates long-term renal oxidative damage and apoptosis in a sex-dependent manner in rats treated with cisplatin (CIS), despite mannitol's nephroprotective effects. We investigated whether repeated exposure to social-single prolonged stress (social-SPS) modulates long-term renal oxidative damage and apoptosis in male and female rats treated with CIS and mannitol. Male and female Wistar rats were divided into three groups: control, CIS + mannitol, and CIS + mannitol + social-SPS. Mannitol was administered 1 h before CIS (2 mg/kg/day, i.p., for 5 days). Social-SPS was applied at three time points. At postnatal day 68, blood and kidney samples were collected for biochemical and Western blot analyses. Plasma renal biomarkers remained unchanged across groups. However, social-SPS increased renal lipid peroxidation (TBARS) and protein oxidation (carbonyl content) in both sexes. CIS+social-SPS decreased catalase activity and altered SOD, GST, and NPSH in a sex-dependent manner. Only female rats showed increased renal BAX/Bcl2 ratio, indicating apoptosis. In males, Na⁺/K⁺-K-ATPase activity correlated positively with NPSH content. Despite mannitol nephroprotection, social stress exacerbated renal oxidative stress. Female rats were more susceptible to apoptosis, suggesting sex-specific vulnerability to combined CIS and stress exposure. These findings highlight the importance of considering psychological stress and sex as modulators of chemotherapeutic toxicity and may inform future strategies for personalized cancer care.

Keywords: apostosis; chemotherapy; cisplatin; sex‐differences; stress.

Figure 1

Schematic representation of the experimental protocol. On PNDs 35, male and female Wistar rats were exposed to social‐SPS and received a dose of 2 mg/Kg of CIS daily until PND 39. Rats were re‐exposed to social‐SPS in PND 45 and PND 55. At PND 68, rats were euthanized, and trunk blood and kidney samples were collected to ex vivo analyses. CIS means cisplatin, PND means postnatal day, social‐SPS means social‐single prolonged stress.

Figure 2

Effects of social‐SPS on oxidative stress markers in kidneys of male and female rats exposed to CIS. TBARS levels (A), Carbonyl Protein levels (B), CAT (C), GST (D), and SOD activities (E) in the kidneys of male and female Wistar rats exposed to CIS. Results represent the mean ± S.E.M. of 8 rats per group. Data analysis was carried out through two‐way or one‐way ANOVA followed by Tukey posttest. The symbol denotes a significant difference compared to the control group, *p < 0.05, **p < 0.01. The symbol (#) denotes a significant difference compared to the CIS group, #p < 0.05, ##p < 0.01, ###p < 0.001, ####p < 0.0001. CIS means cisplatin, social‐SPS means social single prolonged stress.

Figure 3

Effects of social‐SPS on NPSH content and Na⁺, K⁺‐ ATPase activity in kidneys of male and female rats exposed to CIS. Effects of social‐SPS on the NPSH levels (A) and Na⁺, K⁺—ATPase activity (B) in kidneys of male and female Wistar rats exposed to CIS. Results represent the mean ± S.E.M. of 8 rats per group. Data analysis was carried out through two‐way (Na⁺, K⁺—ATPase) or one‐way ANOVA followed by Tukey posttest (NPSH). The symbol (*) denotes a significant difference compared to the control group, *p < 0.05, **p < 0.01, and ****p < 0.0001. The symbol (#) denotes a significant difference compared to the CIS group, ###p < 0.001. The symbol (%) denotes a significant difference between male CIS+ social‐SPS and female CIS + social‐SPS, %% p < 0.01. CIS means cisplatin, social‐SPS means social single prolonged stress.

Figure 4

Effects of social‐SPS on apoptotic protein levels in male and female rats exposed to CIS. Effects of social‐SPS on the BAX/Bcl2 protein level ratio (A) in the kidneys of male and female rats exposed to CIS. Representative bands of BAX/Bcl2 proteins are shown at the bottom of the figure. Results represent the mean ± S.E.M. of 6 rats per group. Data analysis was carried out through two‐way ANOVA followed by Tukey posttest. The symbol (*) denotes a significant difference when compared to the control group, **p < 0.01. The symbol (%) denotes a significant difference when compared to male CIS+ social‐SPS and female CIS + social‐SPS. %%%p < 0.001. CIS means cisplatin, social‐SPS means social single prolonged stress.

Figure 5

Summary effects of Social‐SPS on kidney and plasma of male and female rats exposed to CIS. Effects on male (dark blue arrows) and female (red arrows) rats are represented here. No alterations in renal plasma biomarkers were observed in male and female rats treated with CIS and exposed to social‐SPS. Social‐SPS exposure increased oxidative stress in the kidneys of male and female rats, showing to enhance NPSH content in both sexes and Na⁺, K⁺—ATPase activity only in males. A proapoptotic pattern was showed in kidneys of female rats treated with CIS and exposed to social‐SPS. Adenosine triphosphate (ATP), adenosine diphosphate (ADP), B‐cell lymphoma 2 (Bcl2), Bcl2‐associated X (BAX).