Interaction of exposure concentration and duration in determining the apoptosis of testis in rats after cigarette smoke inhalation

Effects and possible mechanisms of combined exposure to noise and carbon monoxide on male reproductive system in rats

Environmental hazards are an increasing concern due to the rapid pace of industrialization. Among these hazards, noise and carbon monoxide (CO) are common risk factors and have been shown to cause serious health problems. However, existing studies focused on the individual effects of noise and CO exposure and the combined effects of these two factors remain poorly understood. Our study aimed to examine the combined effects of noise and CO exposure on testicular function by constructing individual and combined exposure models. Our findings indicated that combined exposure to noise and CO was associated with a higher risk of testicular damage and male reproductive damage when compared to exposure alone. This was evidenced by poorer semen quality and more severe pathological damage to the testis. This combined exposure led to higher levels of oxidative stress and apoptosis in the testes, with bioinformatics analyses suggesting the signaling pathways involved in these responses. Specifically, activation of the P53 signaling pathway was found to contribute to the testicular damage caused by the combined exposure. Encouragingly, pterostilbene (PTE), a novel phytochemical, alleviated combined exposure-induced testicular damage by reducing oxidative stress and germ cell apoptosis. Overall, we identified joint reproductive toxicity resulting from the exposure to noise and CO, and found that PTE is a promising potential treatment for injuries caused by these factors. The cover image is based on the Research Article Effects and possible mechanisms of combined exposure to noise and carbon monoxide on male reproductive system in rats by Yingqing Li et al., https://doi.org/10.1002/tox.23927.

Testicular tissue response following a 90-day subchronic exposure to HTP aerosols and cigarette smoke in rats

Background

Researches have shown that chronic inhalation of cigarette smoke (CS) disrupts male reproductive system, but it is unclear about the mechanisms behind reproductive damages by tobacco toxicants in male rats. This study was designed to explore the effects of heated tobacco products (HTP) aerosols and CS exposure on the testicular health of rats.

Materials and Methods

Experiments were performed on male SD rats exposed to filtered air, HTP aerosols at 10 μg/L, 23 μg/L, and 50 μg/L nicotine-equivalent contents, and also CS at 23 μg/L nicotine-equivalent content for 90 days in five exposure groups (coded as sham, HTP_10, HTP_23, HTP_50 and Cig_23). The expression of serum testosterone, testicular tissue inflammatory cytokines (IL-1β, IL-6, IL-10, TNF-α), reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA), NLRP3 inflammasome-related mRNAs and proteins (NLRP3, ASC, and Caspase-1), the degree of pyroptosis and histopathology were investigated.

Results

The results demonstrated that HTP_50 and Cig_23 caused varying degrees of oxidative damage to rat testis, resulting in a decrease of sperm quantity and serum testosterone contents, an increase in the deformity rate, expression levels of proinflammatory cytokines, and NLRP3 inflammasome-related mRNA, and an increase in the NLRP3, ASC, and Caspase-1-immunopositive cells, pyroptosis cell indices, and histopathological damage in the testes of rats. Responses from the HTP_10 and HTP_23 groups were less than those found in the above two exposure groups.

Conclusion

These findings indicate that HTP_50 and Cig_23 induced oxidative stress in rat testes, induced inflammation and pyroptosis through the ROS/NLRP3/Caspase-1 pathway, and destroyed the integrity of thetesticular tissue structure.

Passive smoking induces rat testicular injury via the FAS/FASL pathway

The mechanisms by which cigarette smoke (CS) exposure has a detrimental effect on the male reproductive system is still not fully understood. We aimed to elucidate the role of cigarette smoke-induced injury by the Fas/FasL pathway by using a Sprague-Dawley rat model of cigarette smoking exposure. Here, 200 rats were randomaly divided into five groups with different smoking exposure durations. Forty animals per group were further divided into four groups: a control group, and groups exposed to cigarette smoke at doses of 10, 20 or 30 cigarettes/day. The testes were harvested and the effects of CS exposure on the testis were characterized on the basis of morphological changes, oxidative stress, and a significant elevation in the expression of FAS/FASL pathway related genes, such as FAS, FASL, FADD, caspase 8 and caspase 3. Oxidative stress was reflected by significant time-dependent changes in SOD and GSH-Px activity, and MDA content. Taken together, our data suggest that CS exposure induces testis injury, which is related to the increased oxidative stress and activation of the FAS/FASL apoptotic pathway in the testes.

Differential expression of TLRs and AKAP3 in cigarette smoked mice testis

Toll-like receptors (TLRs) are expressed in Sertoli cells and Leydig cells and can initiate testicular innate immune responses. The A-kinase anchor protein 3 (AKAP3), a family of scaffolding protein, was reported to be expressed only in testis and plays important regulatory roles during spermatogenesis. Our present study aimed to investigate the differential expression of TLRs family and AKAP3 in cigarette smoked Kunming mice testis. To check the effect of cigarette smoke, mice were randomly divided (n = 5 each) and exposed to cigarette smoke (2 hr/day with 10 cigarettes) for six consecutive days followed by one exposure-free day. The exposure lasted for zero (control), 1, 3, 5 and 7 months respectively. The IHC results showed that expression of AKAP3 protein is mainly located in sperm cells and the mean density of which was significantly lower than that of control mice. Real-time PCR results showed that expression of AKAP3 was significantly increased at early CS exposure (1 month) and then returned to normal in subsequent months. TLR2-7, TLR13, Myd88 and Traf6 mRNA expression are much lower compared to control, especially after 3-month cigarette smoke exposure, the time of which is almost consistent with sperm cycle. The present study suggests that TLR signal pathway and AKAP3 may play roles in spermatogenesis.

Effect of lipid lowering tablet on blood lipid in hyperlipidemia model rats

Observe the effect of lipid-lowering tablets on body weight, liver index and serum biochemical indexes of hyperlipidemia rats. The hyperlipidemia rat model was replicated successfully. Compared with the model group, high, medium and low dose lipid-lowering tablets group could significantly increase the body weight of rats with hyperlipidemia (P < 0.01, P < 0.05); High and middle dose lipid-lowering tablets group could significantly reduce the liver index of high fat rat (P < 0.01); High, medium and low dose lipid-lowering tablets group could significantly decrease levels of TC, TG, LDL-C, AST, ALT, ALP, Y-GT in serum (P < 0.01, P < 0.05), and significantly increase the level of HDL-C (P < 0.01). Lipid-lowering tablets can effectively regulate the body lipid metabolism of rats, and have a certain therapeutic effect on hyperlipidemia.