Proton pumps are membrane-bound enzymes important in generating gradients that help in maintaining cellular ion homeostasis, cell membrane potential, water, and solute transport across the cell surface. This study investigated the modulatory role of vitamin E on proton pump activity and reproductive parameters in cadmium-induced testicular damage. Twenty (20) male Wistar rats weighing between 180 and 200 g were sorted into 4 groups of five rats each. Group I served as the control and was given normal saline orally, Group II rats were treated with a single dose of 2 mg/kg BW cadmium chloride (CdCl2) intraperitoneally, Group III rats were given 100 mg/kg BW of vitamin E orally, and Group IV rats were given 100 mg/kg BW of vitamin E orally for 30 days prior to intraperitoneal administration of single dose of 2 mg/kg BW of cadmium chloride. The rats were anaesthetized with diethyl ether, and blood samples were obtained for sex hormonal analysis; caudal epididymis was dissected for sperm count, motility, and viability, and the testis were homogenized for lipid peroxidation and proton pump (Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase) activity. Proton pump activity was assayed spectrophotometrically using the Stewart method to determine the inorganic phosphate level. Histopathological changes of the testis were also studied. The group treated with CdCl2 showed a significant ( p < 0.05 ) decrease in proton pump activity, sperm count, and motility and a significant ( p < 0.05 ) increase in malondialdehyde level when compared with the control group. The CdCl2-treated group also showed decrease reproductive organ weights and hormonal levels and cause necrosis of spermatogonia lining the seminiferous tubules. Rats treated with vitamin E orally for 30 days prior to CdCl2 exposure showed improvement in proton pump activity, a significant ( p < 0.05 ) increase in sperm parameters and luteinizing hormonal level, and a decrease in the lipid peroxidation level as compared with the CdCl2 group. This study showed that vitamin E ameliorated the toxic effect of CdCl2 on proton pump activity in the testes, hence improving testicular integrity, structures, and functions.

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Natural carotenoids from green microalgae exhibit beneficial effects in treating health-related diseases, primarily due to their antioxidant capacity. Therefore, carotenoid-producing microalgae were isolated and characterized from aqueous samples in KwaZulu-Natal (South Africa) under photoautotrophic conditions. Three isolates were characterized comprehensively using light and electron microscopy. In addition, the growth of the three selected microalgae was evaluated under photoautotrophic and photoheterotrophic conditions. Based on the cytological characteristics, the three strains matched the genera Haematococcus, Parachlorella, and Scenedesmus, the latter two additionally confirmed via analysis of the 18S rRNA gene sequence at the genus level. Light and electron microscopy and UV-Vis spectroscopy confirmed pigment production by all three microalgal strains. Both isolate Parachlorella sp. AA1 and Scenedesmus sp. AA2 showed the highest growth rate when cultured with acetate (25 mM) photoheterotrophically, while the isolate Haematococcus sp. AA3 grew best with glucose (50 mM). In addition, all three isolates utilized salicylate as a carbon source under photoheterotrophic conditions, evidently resulting in increased carotenoid production in strains AA1 and AA3. The 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) antioxidant assay confirmed that methanol extracts of all three isolates contained carotenoids that can scavenge radicals, and thin layer chromatography (TLC) analysis showed that β-carotene and astaxanthin were formed by strain AA3 as main carotenoids.