Prevenção do estresse oxidativo na síndrome de isquemia e reperfusão renal em ratos com suplementação nutricional com antioxidantes

Effects of topical ketorolac tromethamine on tear parameters, meibography, goblet cell density, and conjunctival oxidative stress in healthy dogs

OBJECTIVES

The objective of the study was to evaluate whether a twice-daily instillation of 0.45% preservative-free ketorolac tromethamine (FKT) or 0.4% benzalkonium chloride-preserved ketorolac tromethamine (BACKT), every 12 h for 30 days may affect tear film parameters and the meibography in healthy dogs. Additionally, we assessed whether the same treatments irritated the ocular surface, affected goblet cell density (GCD), and the levels of oxidative stress biomarkers (OSB) in the conjunctiva of the same dogs.

PROCEDURES

Experimental and masked comparison study. In 11 healthy dogs baseline values of the lipid layer thickness, tear meniscus height, non-invasive tear breakup time (NI-TFBT), and the meibomian gland (MG) loss were assessed by OSAvet®. For each dog, one eye received 40 μL of BACKT, while the other received 40 μL FKT, every 12 h for 30 consecutive days. Tear parameters and meibography were repeated 15, 30, and 60 days post-treatments. Conjunctival hyperemia and blepharospasm were monitored at the same time points. At baseline and Day 30, a conjunctival biopsy was collected for GCD and OSB determination.

RESULTS

Conjunctival hyperemia and blepharospasm were not observed. At Day 15, the MG loss increased only in FKT-treated eyes (p < .001). On Day 30, both treatment groups showed increased MG loss, shortened NI-TFBT, and reduced GCD and catalase (p < .05). At Day 30, BACKT-treated eyes showed lower levels of superoxide dismutase (SOD) (p = .006) and higher levels of malondialdehyde (MDA) (p = .02). Differences between treatments were not observed for any parameter at any time point (p > .05). 60 days after treatment, OSAvet® parameters tended to return to values assessed at baseline; however, significant differences remained for MG loss (p < .05).

CONCLUSIONS

Twice-daily instillation of KT, containing or not BAC, for 30 consecutive days shortened NI-TFBT, decreased GCD, and increased the MG loss in healthy dogs. KT should be used with caution when prescribed for long periods, particularly in patients with tear film abnormalities. However, future controlled studies using KT, BAC, and other topical NSAIDs are indicated to further support this finding.

Ischemic perconditioning on mesenteric ischemia/reperfusion injury in rats

Purpose:

To evaluate if the perconditioning affects the antioxidant capacity in mesenteric ischemia and reperfusion injury.

Methods:

Twenty-one Wistar rats were assigned into three groups, as follows: Sham, IR and rPER. The animals were subjected to mesenteric ischemia for 30 min. rPER consisted of three cycles of 5-min hindlimb ischemia followed by 5 min hindlimb perfusion at the same time to mesenteric ischemic period. After 5 minutes, blood and 5 cm of terminal ileum were harvested for thiobarbituric acid reactive substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC) measurement.

Results:

rPER technique was able to reduce intestinal tissue TBARS levels (p<0.0001), but no statistic difference was observed in blood levels between groups, although it was verified similar results in rPER and Sham group. rPER technique also enhanced TEAC levels in both blood (p = 0.0314) and intestinal tissue (p = 0.0139), compared to IR group.

Conclusions:

rPER appears as the most promising technique to avoid IR injury. This technique reduced TBARS levels in blood and intestinal tissue and promoted the maintenance of antioxidant defense in mesenteric acute injury.

Remote ischemic conditioning protects against testicular ischemia∕reperfusion injury in rats

Purpose

To evaluate the effect of remote ischemic conditioning associated to N-acetylcysteine (NAC) on testicular ischemia∕reperfusion (I∕R) injury in rats.

Methods

Twenty-five adult male Wistar rats were randomly distributed into five experimental groups (n=5), as follows: Sham, I∕R, Perconditioning (PER), NAC and PER+NAC. Two-hour ischemia was induced by rotating the left testis 720° to clockwise direction, followed by 4 hours of reperfusion. Perconditioning was performed by three I/R cycles of 10 min each on the left limb, 30 min before reperfusion. N-acetylcysteine (150 mg∕kg) was administered 30 min before reperfusion.

Results

Statistical differences were observed in MDA levels between I/R group with all groups (p<0.01), in addition there was statistical difference between PER and Sham, and PER+ NAC groups (p<0.05) in plasma.

Conclusions

The protective effect of perconditioning isolated in the reduction of lipid peroxidation related to oxidative stress was demonstrated. However, when Perconditioning was associated with NAC, there was no protective effect against testicular injury of ischemia and reperfusion.

Efeito protetor do per-condicionamento isquêmico remoto nas lesões da síndrome de isquemia e reperfusão renal em ratos

OBJETIVO: Avaliar o efeito protetor do per-condicionamento isquêmico remoto nas lesões de isquemia e reperfusão renal induzida. MÉTODOS: Quinze ratos (Rattus Novergicus) foram randomizados em três grupos (n=5): Grupo Normalidade (GN), Grupo Controle - Isquemia e Reperfusão (GIR) e Grupo Per-condicionamento isquêmico remoto (GPER). Com exceção do grupo GN, todos os demais foram submetidos à isquemia renal de 30 minutos. No grupo GPER, foi realizado o per-condicionamento isquêmico remoto, constituído de três ciclos de isquemia e reperfusão de cinco minutos cada aplicado, durante o período de isquemia, no membro posterior esquerdo dos ratos, por meio de torniquete. Para quantificar as lesões, foram dosados os níveis séricos de ureia e creatinina, bem como, analisada a histopatologia renal. RESULTADOS: O grupo GPER apresentou-se com melhores níveis de ureia (83,74 ± 14,58%) e creatinina (0,72 ± 26,14%) quando comparado ao grupo GIR, se aproximando do grupo GN. Na histopatologia, os menores níveis de degeneração hidrópica e congestão medular foram encontrados no grupo GPER. CONCLUSÃO: O per-condicionamento isquêmico remoto apresentou importante efeito protetor na lesão de isquemia e reperfusão renal.