Lead Acetate Trihydrate: Detection Applications and Toxicity

Lead acetate trihydrate is defined as a white crystalline compound of lead, also known as "sugar of lead," that is water-soluble and highly poisonous. It is commonly used in various applications such as textile dyeing, metal coatings, and as a colorant in hair dyes. Lead acetate trihydrate is also toxic like other lead compounds. But it still has various applications such as a fixative and also as a reagent for synthesis of other compounds. It was also used as a sweetener but soon it was banned due to its toxic nature. It was discovered in the US in 1944.

Novel Applications of Lead acetate trihydrate and Detection of Sulfur-Containing Molecules

Hydrogen sulfide (H2S), previously only considered a hazardous gas, was, in the 1990s, detected in mammalian tissues and found indispensable in physiological concentrations. H2S is biosynthesized through enzymatic reactions in human tissues, although 50% of this gas is generated by the microbiota, in the inner and outer mucus layers of the intestine. Measurements of free H2S can be attained using the agar trap method, which is based on the methylene blue reaction. Other colorimetric methods, based on reactions with silver ions, bismuth (III) chloride and potentiometric methods, were developed to detect H2S production. These last methods generally are time- and work-consuming procedures and/or their accuracy has been criticized. On the other hand, we were intrigued from acknowledging that the e strips test, used to detect H2S produced by microorganisms and to evaluate the quality of water and food, although declared by the producer “the more sensitive than any other method for detecting hydrogen sulfide production”, has never been used, for quantitating H2S release in cell cultures, on a routine basis. We have indeed here developed a new protocol for the application of the lead acetate trihydrate strip test to cell cultures. The aim of this part of the experimental design was to set the conditions for the use of the lead acetate trihydrate strip test (LAST) to quantitate H2S release from cell cultures. In this phase, indeed, LAST assays were performed in parallel with another well-established test usually employed to evaluate the release of H2S in vitro.[1]

The lead acetate trihydrate strip test was successfully adapted to quantify H2S release in cell culture and, compared with agar trap, was equally sensitive, during the first hour of incubation. Standard curves, for the agar trap and LAST methods, showed linear or exponential dependence of the amount of H2S released as a function of NaHS concentration. The sensitivity of the two methods appeared comparable. In these experiments, NaHS, used as H2S donor, was dissolved in an aqueous solution and, hence, released as H2S is measured. For LAST, we used 4 mm Ø lead acetate trihydrate treated filters. Thus, the minimal amount of sulfur containing solute to be detected was 0.28 μg to be absorbed onto 1 mm2 filter surface. Saturation was reached at 4.5 μg/mm2. Agar trap method displays similar performances compared to LAST with respect to the lower threshold sensitivity level. Conversely, saturation was reached at lower NaHS amount (about 45 μg), corresponding to 160 μM NaHS in solution. We figured out that sensitivity of LAST and agar trap methods could be further increased by 25%, by reducing surface area of the lead acetate trihydrate filter and by reducing gel surface, thus optimizing detection solution volume, respectively. The new application methods for H2S determination appear to be fully suitable for the analysis of H2S release and sulfane sulfur content in biological samples.

Long-Term Exposure of Lead Acetate Trihydrate

Lead has been extensively used in different industries for thousands of years. Relevance between lead poisoning and renal disease in humans has been recognized for more than a century. Lead is one of the most important air pollutants and poisonous even at low concentration. There are few ultrastructural studies about the lead effects on the kidney on laboratory models. Hence, the aim of this study was the evaluation of histopathological effects of long-term exposure of lead acetate trihydrate on the renal tissue in rabbit. In this experimental study, 20 male New Zealand rabbits weighing 1400 - 1500 g were exposed to the chronic dose of lead acetate. All the experiments were approved by the Ethics Committee of Bushehr University of Medical Sciences. The rabbits were divided into control and test groups (10 in each) and housed in cages separately and fed on pellet and water with no restrictions. The animals were kept in standard laboratory conditions at 22 - 24°C and relative humidity of 40-60%, with 12-hour light/dark cycles. The test group was injected with 8.5 mg/kg of body weight (BW) of lead acetate trihydrate intraperitoneal; but, for the control group, the same volume of the sterile normal saline was used every other day for 10 weeks of intervention.[2]

So far, the reports have shown many side-effects of lead on the function of kidney tissue; while in the present study, the morphologic and morphometric results were evaluated by long-term exposure to the chronic dose of lead acetate trihydrate. Here, by evaluations of the qualitative results from light photomicrographs, were showed that lead exposure caused dilation in distal convoluted tubules, proximal convoluted tubules and collecting ducts. In addition, the thickness of epithelial cells of tubules decreased and the nuclei of epithelial cells were found to be more heterochromatic. Damage to the renal corpuscles indicated the destruction of mesangial tissue in the vascular pole of corpuscles. The report from Jabeen et al. showed that lead acetate trihydrate decreased the renal cortical thickness and the diameter of corpuscles significantly and induced the moderate cortical tubular atrophy, indicating the thickening of glomeruli basement membrane; morphometric results of this study are in line with the above findings. In agreement with the above findings, our morphometric and morphologic results showed an increase in the dilatation of renal tubules and disarrangement of interstitial tissues following long-term exposure to lead acetate. Moreover, the ultrastructural findings showed an increase in the thickness of basement membrane of urinary filtration barrier. In conclusion, the morphologic and morphometric findings of this study showed that long-term exposure to lead acetate trihydrate caused renal tubules dilatation, congestion, nuclei heterochromatic changes, decreased tubules epithelial thickness, and increase in the thickness of urinary barrier, which finally lead to renal dysfunctions.

Protective effects of piperine on lead acetate trihydrate induced-nephrotoxicity

Lead acetate trihydrate is a biotoxic environmental and industrial pollutant, which accumulates in almost all body tissues such as the liver, lung, bones, kidneys, reproductive organs, and the immune system. Several studies have shown that obtained piperine from Piper longum L and Piper nigrum L has remarkable biological activities such as antioxidant, anti-inflammatory, analgesic, antihyper- tensive, antitumoraland, antibacterial. In the present study, the protective effects of piperine were investigated on lead acetate trihydrate -induced renal damage in rat kidney tissue.[3]

The results revealed that lead acetate toxicity induced a significant increase in the levels of BUN, creatinine, and MDA; moreover, a significant decrease in SOD and GPx. Lead acetate trihydrate also altered kidney histopathology (kidney damage, necrosis of tubules) compared to the negative control. However, administration of piperine significantly improved the kidney histopathology, decreased the levels of BUN, creatinine, and MDA, and also significantly increased the SOD and GPx in the kidney of lead acetate trihydrate -treated rats.

References

[1]Anishchenko E, Vigorito C, Mele L, Lombari P, Perna AF, Ingrosso D. Novel Applications of Lead Acetate and Flow Cytometry Methods for Detection of Sulfur-Containing Molecules. Methods Protoc. 2019 Feb 1;2(1):13. doi: 10.3390/mps2010013. PMID: 31164595; PMCID: PMC6481055.

[2]Karimfar MH, Bargahi A, Moshtaghi D, Farzadinia P. Long-Term Exposure of Lead Acetate on Rabbit Renal Tissue. Iran Red Crescent Med J. 2016 Feb 6;18(2):e22157. doi: 10.5812/ircmj.22157. PMID: 27195142; PMCID: PMC4867333.

[3]Sudjarwo SA, Eraiko K, Sudjarwo GW, Koerniasari. Protective effects of piperine on lead acetate induced-nephrotoxicity in rats. Iran J Basic Med Sci. 2017 Nov;20(11):1227-1231. doi: 10.22038/IJBMS.2017.9487. PMID: 29299200; PMCID: PMC5749357.