Oxytetracycline-induced oxidative liver damage by disturbed mitochondrial dynamics and impaired enzyme antioxidants in largemouth bass (Micropterus salmoides).

Oxytetracycline (OTC), a commonly used tetracycline antibiotic in aquaculture, has been found to cause significant damage to the liver of largemouth bass (Micropterus salmoides). This study revealed that OTC can lead to severe histopathological damage, structural changes at the cellular level, and increased levels of reactive oxygen species (ROS) in M. salmoides. Meanwhile, OTC impairs the activities of antioxidant enzyme (such as T-SOD, CAT, GST, GR) by suppressing the activation of MAPK/Nrf2 pathway. OTC disrupts mitochondrial dynamics and mitophagy through via PINK1/Parkin pathway. The accumulation of damaged mitochondria, combined with the inhibition of the antioxidant enzyme system, contributes to elevated ROS levels and oxidative liver damage in M. salmoides. Further investigations demonstrated that an enzyme-treated soy protein (ETSP) dietary supplement can help maintain mitochondrial dynamic balance by inhibiting the PINK1/Parkin pathway and activate the MAPK/Nrf2 pathway to counteract oxidative damage. In summary, these findings highlight that exposure to OTC disrupts mitochondrial dynamics and inhibits the antioxidant enzyme system, ultimately exacerbating oxidative liver damage in M. salmoides. We propose the use of a dietary supplement as a preventive measure against OTC-related side effects, providing valuable insights into the mechanisms of antibiotic toxicity in aquatic environments.

The Effects of Creatine Supplementation on Explosive Performance and Optimal Individual Postactivation Potentiation Time.

Creatine plays an important role in muscle energy metabolism. Postactivation potentiation (PAP) is a phenomenon that can acutely increase muscle power, but it is an individualized process that is influenced by muscle fatigue. This study examined the effects of creatine supplementation on explosive performance and the optimal individual PAP time during a set of complex training bouts. Thirty explosive athletes performed tests of back squat for one repetition maximum (1RM) strength and complex training bouts for determining the individual optimal timing of PAP, height and peak power of a counter movement jump before and after the supplementation. Subjects were assigned to a creatine or placebo group and then consumed 20 g of creatine or carboxymethyl cellulose per day for six days. After the supplementation, the 1RM strength in the creatine group significantly increased (p < 0.05). The optimal individual PAP time in the creatine group was also significant earlier than the pre-supplementation and post-supplementation of the placebo group (p < 0.05). There was no significant difference in jump performance between the groups. This study demonstrates that creatine supplementation improves maximal muscle strength and the optimal individual PAP time of complex training but has no effect on explosive performance.

[The protective mechanism study of fengshiqing recipe against bone destruction in CIA rats].

OBJECTIVE: To explore the protective mechanism of Fengshiqing Recipe (FR) against bone destruction in collagen-induced arthritis (CIA) rats. METHODS: Rats were divided into four groups in the experiment,i.e., the blank control group, the model group, the MTX group (MTX, 1 mg/1 000 g), and the FR group (24 g crude FR/kg). The CIA model was prepared except the blank control group. Medication was started in the MTX group and the FR group from the 14th day after modeling to the 56th day. The toe volume was measured on every Tuesday and Friday. Expression levels of serum IL-17, RANKL, MIP-1alpha were detected after 3-and 6-week intervention. The bone scintigraphy with nuclide (SPECT), bone mineral density (BMD), and the pathological section were observed to assess the intervention of drugs of heat clearing blood activating actions in the bone destruction of CIA rats. RESULTS: From the 10th day of modeling, the volume of both toes started to swell and reached the peak at about 21 days. It was obviously shrunk at about 30 days. Of them, the swelling degree was milder in the MTX group and the FR group than in the model group. Compared with the model group at the same phase, the levels of IL-17 and RANKL decreased in the MTX group after 3 weeks of intervention (P < 0.01, P < 0.05). The IL-17 level decreased in the FR group after three weeks of intervention (P < 0.05). The RANKL level decreased in the MTX group and the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). Compared with the model group and the MTX group, the overall BMD and ankle BMD increased in the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). The ankle ROI/mandible and the toe ROI/mandible were elevated in the FR group after 3 weeks of intervention (P < 0.05). Pathological results suggested that the joint lacunae was significantly widened, the hyperplasia of the synovial tissue was so severe, and the bone tissue was destroyed in the model group. Compared with the model group, the aforesaid conditions were significantly improved in the MTX group and the FR group. The cartilage structure was complete. CONCLUSION: QR could inhibit decreased BMD, prevent bone destruction, which might be achieved by down-regulating expression levels of IL-17, RANKL, and MIP-1alpha through the osteo immunological Th/RANKL system,inhibiting maturation and differentiation of osteoclasts, thereby, inhibiting bone destruction.

The protective effect of EGB761 on vessels of denervated gastrocnemius in rats and its mechanism.

This study investigated the protective effect of EGB761 on blood vessels of denervated gastrocnemius of rat and its possible mechanism. Fifteen male adult SD rats were randomly divided into three groups: normal control group (n=3), control group (n=6) and EGB761-treated group (n=6). The rats in the control and EGB761-treated group underwent a neurotomy to bilateral sciatic nerves. Then, they were administered EGB761 [100 mg/(kg·d)] and isovolumic normal saline, respectively by gavage everyday. No treatment was given to the rats in the normal control group. Gastrocnemius was harvested at 1 and 3 week(s) postoperatively in each group. Immunohistochemical method was used to detect the ratio of capillary/fiber (CFR) of denervated gastrocnemius and the expression of VEGF, fetal liver kinase -1(Flk-1) receptor and HSP70 in the vascular wall. The results showed that in the normal control group, VEGF, Flk-1 and HSP70 were expressed in the vessel wall of gastrocnemius, with Flk-1 expressed only in the endothelial cell of vessels. CFR in the EGB761-treated group was significantly higher than that in the control group at 1 week and 3 week(s) after neurotomy. The expression of VEGF and Flk-1 in the vessel wall of both control and EGB761-treated group was much lower than that in the normal control group, and the expression of these proteins in the EGB761-treated group was decreased as compared with that in the control group. The expression of HSP70 in the vessel wall of both control and EGB761-treated groups was enhanced when compared with that in the normal control group, and it was substantially augmented in the EGB761-treated group in comparison to the control group. It was concluded that EGB761 has a protective effect on blood vessels of denervated gastrocnemius, which is related to the increased HSP70 expression but not the expression of VEGF and its receptor Flk-1.