Xanthine oxidase (XO) is an important therapeutic target for the treatment of hyperuricemia and gout. Based on the previously identified potent XO inhibitor 1, seventeen oxadiazoles and their ring-opening analogues were designed and synthesized via the bioisostere replacement strategy. Among them, compounds 2l, 2n, and 3b showed obvious XO inhibitory activity at the concentration of 10 μmol·L^-1, and compound 3b exhibited an IC₅₀ value of 1.45 μmol·L^-1.

Autoimmune hepatitis （AIH） is an autoimmune disease characterized by liver parenchymal destruction and chronic fibrosis， and it is often mediated by T cells. The pathogenesis of AIH involves multiple factors， including sex， region， environmental factors， and genetic susceptibility. A notable predisposition is observed in female individuals， and the incidence rate of AIH in female individuals is significantly higher than that in male individuals. This sex difference is associated with various factors， and sex hormones may be an important cause of the female predominance of AIH， although the specific mechanisms remain unclear. An in-depth understanding of the mechanism of action of sex hormones in the pathogenesis of AIH will help to better understand the pathogenesis of the disease and may provide important clues for developing future treatment methods and prevention strategies. This article reviews the mechanism of action of estrogen and androgen in regulating the pathogenesis of AIH by regulating T cells， in order to provide new ideas and directions for further exploring the potential role of sex hormones in the etiology of autoimmune diseases.

Objective To investigate the level of deltamethrin resistance and mutation sites in the sodium iron channel gene in Rhipicephalus microplus in Huaihua City, Hunan Province, and to examine the correlation between deltamethrin resistance and mutation sites in the sodium iron channel gene in Rh. microplus. Methods Rh. microplus was sampled from multiple yellow cattle farms in Huaihua City, Hunan Province from June to September 2022, and the level of resistance to deltamethrin was determined in ticks using the adult immersion test. The sodium iron channel domain III gene was amplified in deltamethrin-resistant and wild-type Rh. microplus using PCR assay. Following sequencing and sequence alignment, mutation sites were detected in bases. The sodium iron channel domain III gene in Rh. microplus was translated, and the signal peptide, transmembrane domain, and phosphorylation and glycosylation sites were detected in amino acid sequences. The tertiary structures of the sodium iron channel domain III protein of deltamethrin-resistant and wild-type Rh. microplus were deduced and compared, and the association be tween mutation sites in bases and resistance to deltamethrin was examined in Rh. microplus according the level of deltamethrin resistance, sequence alignment and protein tertiary structure. Results The median (LC₅₀) and 95% lethal concentrations (LC₉₅) of deltamethrin were 121.39 mg/L and 952.61 mg/L against Rh. microplus, with a resistance factor of 9.24 and level II resistance. The sequence of the sodium ion channel domain III gene was 1 010 bp in size, and mutation sites were detected in two neighboring bases in the sequence of the sodium ion channel domain III gene in deltamethrin-resistant Rh. microplus. Although no signal peptides were found in the sodium iron channel domain III protein of deltamethrin-resistant or wild-type Rh. microplus, 6 trans-membrane domains, 42 phosphorylation sites and 8 glycosylation sites were identified, with a significant difference in the tertiary structure of the sodium iron channel domain III protein between deltamethrin-resistant and wild-type Rh. microplus. Conclusions Level II resistance to deltamethrin is detected in Rh. microplus in Huaihua City, Hunan Province, and two mutation sites that correlate with the emergence of deltamethrin resistance are identified in the sequence of the sodium iron channel domain III gene in deltamethrin-resistant Rh. microplus.

Aim To investigate the effect of quercetin on the aging model of bone marrow mesenchymal stem cells established under microgravity. Methods Using 3D gyroscope, a aging model of bone marrow mesenchymal stem cells was constructed, and after receiving quercetin and microgravity treatment, the anti-aging effect of the quercetin was evaluated by detecting related proteins and oxidation indexes. Results Compared to the control group, the expressions of age-related proteins p21, pi6, p53 and RB in the microgravity group significantly increased, while the expressions of cyclin D1 and lamin B1 significantly decreased, with statistical significance (P<0.05). In the microgravity group, mitochondrial membrane potential significantly decreased (P<0.05), ROS accumulation significantly increased (P <0.05), SOD content significantly decreased and MDA content significantly increased (P<0.05). Compared to the microgravity group, the expressions of age-related proteins p21, pi6, p53 and RB in the quercetin group significantly decreased, while the expressions of cyclin D1 and lamin B1 significantly increased, with statistical significance (P<0.05). In the quercetin group, mitochondrial membrane potential significantly increased (P<0.05), ROS accumulation significantly decreased (P<0.05), SOD content significantly increased and MDA content significantly decreased (P<0.05). Conclusions Quercetin can resist oxidation, protect mitochondrial function and normal cell cycle, thus delaying the aging of bone marrow mesenchymal stem cells induced by microgravity.