RESUMO
Sex differences in metabolic dysfunction-associated steatotic liver disease (MASLD) have been reported. Oxidative stress and inflammation are involved in the progression of MASLD. Thus, we aimed to evaluate liver redox homeostasis and inflammation in male and female rats fed a high-fat diet (HFD). Male and female Wistar rats were divided into the following groups: standard chow diet (SCD) or HFD during 12 weeks. HFD groups of both sexes had higher hepatocyte injury, with no differences between the sexes. Portal space liver inflammation was higher in females-HFD compared to females-SCD, whereas no differences were observed in males. Lobular inflammation and overall liver inflammation were higher in HFD groups, regardless of sex. TNF-α, IL-6, and IL-1ß levels were higher in males-HFD compared to males-SCD, but no differences were observed in females. Catalase activity was higher in males compared to females, with no differences between the SCD and HFD groups of both sexes. Glutathione peroxidase activity was higher in females compared to males, with no differences between the SCD and HFD groups in both sexes. Lipid peroxidation was higher in female-SCD when compared to male-SCD, and in both male- and female-HFD compared to SCD groups. Furthermore, both cytoplasmic and nuclear NRF2 staining were lower in the HFD group compared to the SCD group in males. However, female-HFD exhibited reduced nuclear NRF2 staining compared to the female-SCD group. In conclusion, our study demonstrated that while both male and female rats developed metabolic dysfunction-associated steatohepatitis after 12 weeks of HFD, the alterations in inflammatory cytokines and redox balance were sexually dimorphic.
RESUMO
Rational synthesis and simple methodology for the purification of large (35-45 nm in lateral size) and flat (1.0-1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about 100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM, SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60-51% of carbon, 34-45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration below 60 mg L-1. The N-GOQDs demonstrate green luminescence with an emission maximum at 505 nm and sedimentation stability in the cell culture medium.
RESUMO
Microencapsulation is a widely studied cell therapy and tissue bioengineering technique, since it is capable of creating an immune-privileged site, protecting encapsulated cells from the host immune system. Several polymers have been tested, but sodium alginate is in widespread use for cell encapsulation applications, due to its low toxicity and easy manipulation. Different cell encapsulation methods have been described in the literature using pressure differences or electrostatic changes with high cost commercial devices (about 30,000 US dollars). Herein, a low-cost device (about 100 US dollars) that can be created by commercial syringes or 3D printer devices has been developed. The capsules, whose diameter is around 500 µm and can decrease or increase according to the pressure applied to the system, is able to maintain cells viable and functional. The hydrogel porosity of the capsule indicates that the immune system is not capable of destroying host cells, demonstrating that new studies can be developed for cell therapy at low cost with microencapsulation production. This device may aid pre-clinical and clinical projects in low- and middle-income countries and is lined up with open source equipment devices.
