Objective: To analyze the expression of sigma factor in drug resistance gene mutations of Mycobacterium tuberculosis (MTB), so as to provide a reference for the drug resistance mechanism of tuberculosis. Methods: Clinical sputum specimens of outpatients at Tianjin Center for Tuberculosis from 2018 to 2022 were collected. A total of 899 MTB-positive strains were obtained by culture, and 492 phenotypically sensitive strains and 407 phenotypically resistant strains were identified by an in vitro phenotypic drug susceptibility test. Thirty drug-sensitive strains of MTB were randomly selected, and 98 drug-resistant strains with specific resistance phenotypes were chosen; all were subjected to melting curve analysis for detection of drug-resistance gene mutations. The strains were divided into sensitive strains without gene mutation, isoniazid-resistant strains with inhA mutation or katG mutation, rifampicin-resistant strains with rpoB mutation, and multigene mutation-resistant strains with inhA+rpoB mutation or katG+rpoB mutation. The mRNA relative expression of sigma factor was detected by fluorescence quantitative PCR, and the ratio of sigma factor mRNA relative expression between the experimental strain and the standard strain >2 was used to screen for highly expressed sigma factor. The differences in sigma factor mRNA relative expression and high expression rate between drug-resistant gene mutant strains and sensitive strains were analyzed. Results: Thirty sensitive strains and 90 drug-resistant strains were included. Among them, there were 16 strains with inhA mutation, 22 strains with katG mutation, 13 strains with rpoB mutation, 15 strains with inhA+rpoB mutation, and 24 strains with katG+rpoB mutation. Compared to the sigma factors of the sensitive strains, the mRNA expression levels of sigG and sigI in inhA-mutated strains, sigF, sigG, sigH, sigI, sigJ, and sigL in katG-mutated strains, and sigF, sigG, sigH, sigJ, and sigL in rpoB-mutated, inhA+rpoB-mutated, and katG+rpoB-mutated strains were significantly higher (all P<0.05). Additionally, the high-expression rates of sigI in inhA-mutated strains, sigF, sigG, sigI, sigJ, and sigL in katG-mutated and inhA+rpoB-mutated strains, and sigF, sigG, sigH, sigJ, and sigL in rpoB-mutated and katG+rpoB-mutated strains were also higher (all P<0.05). Conclusion Compared to sensitive MTB strains, sigI showed higher relative expression of mRNA and high-expression rate in inhA-mutated strains, and sigF, sigG, sigJ, and sigL had higher mRNA relative expression and high-expression rates in katG-mutated, rpoB-mutated, and multi-drug-resistant strains.

OBJECTIVE To study the pharmacokinetic characters of Baihe -zhimu decoction （BZD） and its single herbs . METHODS A liquid chromatography -tandem mass spectrometry method was developed to simultaneously determine the blood concentrations of 7 effective components （neomangiferin，mangiferin，regaloside A ，regaloside Ⅰ，timosaponin B Ⅱ，timosaponin E and timosaponin A Ⅲ）in rats after oral administration of BZD extract ，single herb extract of Lilium brownii and Anemarrhena asphodeloides. The pharmacokinetic parameters were calculated . RESULTS The linear range of 7 effective components as neomangiferin were 1-1 000，1-1 000，0.1-100，0.4-400，1-1 000，0.1-100 and 0.5-500 ng/mL（all r＞0.998），respectively. The accuracy of the method ranged from 87.50% to 115.00%，and the RSDs of intra -day and inter -day precision were 0.62%-14.35%. RSDs of matrix factor were 2.68%-14.03%，and deviation of stability were within ±15%. Compared with L. brownii and A. asphodeloides，AUC0－24h，AUC0－∞ and cmax of 7 effective components in BZD were increased significantly （P＜0.05），while CL z/Fof 6 effective components （except timosaponin B Ⅱ）decreased significantly （P＜0.05）. CONCLUSIONS BZD can increase the absorption of effective ingredients in rats ，slow down their elimination and prolong their retention time ，indicating pharmacokinetic behaviors of effective components in BZD possess more advantages over those of single herbs .

Objective To investigate the effect of MMP-8 on cornea. Methods Fifteen C57BL/6J healthy mice were selected. The right eyes corneal stroma was injected by 10μL MMP-8 as the experimental group and the left eyes were injected by same amount of normal saline as the control group. At 0,4,8 h, the two-photon microscope second harmonic generation imaging technology was used to scan mice corneal stroma layer by layer in vivo. The obtained images were performed the 3D reconstruction by Imaris software and the signal intensity of the images were calculated. At 4,8 h, the corneal opacity degree was evaluated under slit lamp. At 8 h,mice were killed and corneas were collected to determine the hydroxyproline concentration. Results The cornea stromal fiber signal strengthes at 0 h in the experimental group and control group were (89.7±11.2) and (85.3±7.0),which at 4 h were (14.5±3.4) and (46.6±14. 0) respectively,which at 8 h were (11.0±4.6) and (34.6±12.5) respectively. The cornea stromal signal strength at 4,8 h in the experiemental group was significantly decreased compared with that in the control group (P<0.05) ;the cornea at 4 ,8 h in the experimental group was significantly turbid than that in the control group (P<0.05);the cornea hydroxyproline concentrations detected at 8h in the experiemental group and control group were (0.433±0. 090) μg/mg and (0. 590±0. 133) μg/mg respectively,the experimental group was significantly lower than the control group (F=7. 193,P=0. 014). Conclusion MMP-8 has obvious degradation and destroy effect on mice corneal stroma collagen,which leads to the decrease of corneal opacity.

AIM: To observe the effect of osthole on tricalcium phosphate (TCP) particles-induced calvarial osteolysis in vivo.METHODS:Male ICR mice were randomly divided into sham group , TCP group and osthole group .A mouse calvarial model of osteolysis was established by TCP particles .On the second postoperative day , osthole (20 mg/kg) was locally injected into the calvarium under the periosteum 3 times a week.Two weeks after osthole treatment , blood and calvaria were collected to determine the level of bone turnover markers such as alkaline phosphatase ( ALP) , osteocalcin and tartrate-resistant acid phosphatase ( TRACP) .The periosteum was performed to examine the release of tumor necrosis factor-α(TNF-α), interleukin-6 (IL-6) and IL-1βby ELISA.The calvaria was obtained for histological and molecular analyses.RESULTS:Data from HE and TRACP staining revealed that osthole prevented TCP particles-induced obvious increase in osteoclastogenesis and resorption area in the metaphysis of mouse calvaria .Osthole treatment increased ALP ac-tivity and osteocalcin level , and dncreased the activity of TRACP in the mouse serum compared with TCP group .Further-more, TCP particles-induced the releases of TNF-α, IL-6 and IL-1βwere significantly suppressed by osthole treatment .In addition, Western blot demonstrated that endoplasmic reticulum ( ER) stress markers such as glucose-regulated protein 78 (GRP78) and CAAT/enhancer binding protein homologous protein (CHOP) were significantly up-regulated in TCP parti-cles-implanted calvarial mice , indicating that TCP particles triggered an ER stress response in the mouse calvarial osteolysis model , which obviously attenuated by osthole .CONCLUSION:Osthole inhibits TCP particles-induced calvarial osteolysis in mice, which is mediated by inhibition of ER stress signaling pathway .