Background Lead is a typical persistent environmental pollutant that can accumulate in bones for decades. During pregnancy, alterations in calcium metabolism promote the mobilization of bone lead, resulting in secondary exposure; however, the mechanisms by which pregnancy-associated bone lead mobilization affects maternal renal function remain unclear. Objective To investigate the role of mitochondrial dysfunction in pregnancy-related bone lead mobilization-induced renal injury. Methods Newly weaned female Wistar rats were randomly assigned to a control or a lead-exposed group administered either 0.05% sodium acetate or 0.05% lead acetate in drinking water. Following a 4-week lead exposure and a 4-week washout period, the females were co-housed with healthy age-matched males for mating. Rats were sacrificed at early (gestational day 3) and late (gestational day 17) pregnancystages, respectively. Renal histopathology was assessed using hematoxylin and eosin staining staining. Mitochondria-related indicators, including oxidative stress, inflammatory responses, and energy metabolism, were measured. Differential metabolites were identified using serum metabolomics. Results Renal injury in the lead-exposed pregnant rats progressed in a time-dependent manner, characterized by degeneration of proximal tubular epithelial cells, glomerular hyaline changes, and interstitial inflammatory cell infiltration. Repeated measures ANOVA indicated a significant interaction between the treatment factor (lead exposure) and the temporal factor (gestational stage) on renal injury (P<0.001). Further analysis of mitochondrial function-related indicators in late-pregnancy renal tissue revealed that the lead exposure group exhibited significantly increased levels of malondialdehyde (MDA) and reactive oxygen species (ROS) (P<0.05), accompanied by a reduction in superoxide dismutase (SOD) and reduced glutathione (GSH) activities (P<0.05); regarding inflammatory markers, levels of interleukin-18 (IL-18) and interleukin-1β (IL-1β) were elevated (P<0.01), whereas interleukin-33 (IL-33) was decreased in the lead-exposed group (P<0.05); energy metabolism-related indicators, including adenosine triphosphate (ATP) level, Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase activities, and mitochondrial respiratory chain complexes I, III, and V activities, were significantly reduced (P<0.05) in the lead-exposed gorup. The typical differential metabolite N-methylisoleucine, identified through serum metabolomics analysis, was negatively correlated with blood lead levels, kidney injury scores, and IL-1β, while positively correlated with catalase (CAT) activity and Ca²⁺-Mg²⁺-ATPase. Conclusions Mitochondrial dysfunction may play a critical role in renal injury induced by bone lead mobilization during late gestation.

ABSTRACT:The virulence genes ,hemolytic and antibiotic resistance characteristics from 19 isolated Streptococcus suis se‐rotype 2 in Anhui Province were investigated in this study .The PCR method was developed for detecting cps2J ,mrp ,ep f and sly gene;the plate method and micro‐ELISA were developed for detecting the hemolytic type and hemolytic titer ;the K‐B method was developed for detecting antibiotic resistance of 25 kinds of antibiotics .Results showed that there were 11 strains with the dominant virulence genotype of cps2J+ /mrp+ /ep f+ /sly+ accounting for 57 .9% .All strains were α‐hemolysis orβ‐hemolysis ,with hemolytic titer of 1∶4 to 1∶128 .Strains sensitive to rifapentine ,ceftazidime ,florfenicol and cefazolin was existed in high frequency with the sensitive rates for 84 .2% ,and the resistance to doxycycline ,tetracycline ,bacitracin and sul‐famethoxazole was existed in high frequency with the resistance rates for 82 .9% .The multi‐antibiogram typing was doxycyc‐line ,tetracycline ,bacitracin and sulfamethoxazole account for 63 .2% .In conclusion ,the distribution of virulence genes of S .suis 2 Anhui isolates was similar with that of domestic reported strains ,and there was some differences with that of over‐seas reported strains .CPS ,MRP ,EPF and SLY are important virulence factors and the incompleteness of sly gene had no effect to its haemolyticus .The multi‐antibiotic resistance of S .suis 2 Anhui isolates was serious .There is difference for anti‐biogram typing between S .suis 2 Anhui isolates and those in other areas .