Histopathological features of low-dose organophosphate exposure

The effect of chlorpyrifos oral exposure on the histomorphometric and kidney function in Wistar rat

BACKGROUND

Chlorpyrifos belongs to a broad-spectrum organophosphate insecticide that has high toxicity, is metabolized in the liver by the oxidation reaction, and can inhibit acetylcholinesterase activity. Acetylcholinesterase inhibition generates the reactive oxygen species and induces oxidative stress, which ultimately results in cellular damage like in the kidney. Examining blood urea nitrogen (BUN) levels, creatinine, and kidney histopathology is an appropriate indicator to assess the toxicity of chlorpyrifos to the degree of damage to cells and kidney tissue.

MATERIALS AND METHODS

This research used to determine the effect of duration of exposure to chlorpyrifos and dose-response relationships is important for early detection of the effects of chlorpyrifos toxicity on health. The research study was a true experimental (completely randomized design) consisting of 30 subjects divided into 5 groups. Controlled Group (K1) given 1 mg/kg BW Tween 20 and NaCl 0, 9% until the 56th day. The chlorpyrifos exposed group (P1, P2, P3, and P4) was given chlorpyrifos 5 mg/kg BW for 7, 14, 28, and 56 days. After the treatment, BUN and creatinine levels were measured, and microscopic changes in the kidney were analyzed. The results of BUN, creatinine, and kidney histopathologic were analyzed using the analysis of variance statistical test.

RESULTS

The data result showed that compared to the control group, there were significant increases of BUN and creatinine (P = 0.013 and P = 0.003). Histopathological examinations of kidney glomerulus diameter were also smaller compared to the control group (P = 0.00). All the data measurement indicates significant differences compared to the control group.

CONCLUSIONS

We concluded that sub-chronic oral exposure to chlorpyrifos at low doses can damage the kidneys and cause kidney failure.

Berberine alleviates chlorpyrifos-induced nephrotoxicity in rats via modulation of Nrf2/HO-1 axis

Chlorpyrifos (CPS), an organophosphorus insecticide, is widely used for agricultural and non-agricultural purposes with hazardous health effects. Berberine (BBR) is a traditional Chinese medicine and a phytochemical with anti-inflammatory and anti-oxidative properties. The present study evaluated the effects of BBR against kidney damage induced by CPS and the underlying mechanisms. An initial study indicated that BBR 50 mg/kg was optimal under our experimental conditions. Then, 24 rats (6/group) were randomized into: control, BBR (50 mg/kg/day), CPS (10 mg/kg/day), and CPS + BBR. BBR was administration 1 h prior to CPS. Each treatment was delivered daily for a period of 28 consecutive days using a gastric gavage tube. Compared to CPS-alone treated rats, BBR effectively improved renal function by preventing the rise in serum urea, creatinine, and uric levels. The reno-protective effects of BBR were confirmed through a histological examination of kidney tissues. BBR restored oxidant-antioxidant balance in renal tissues mediated by Keap1/Nrf2/HO-1 axis modulation. In addition, BBR decreased nitric oxide (NO) and myeloperoxidase (MPO) activity. This was paralleled with the potent down-regulation of NF-κB. Furthermore, BBR exhibited anti-apoptotic activities supported by the upregulation of Bcl-2 and down-regulation of Bax and caspase-3 expression. In conclusion, our data suggest that BBR attenuates CPS-induced nephrotoxicity in rats by restoring oxidant-antioxidant balance and inhibiting inflammatory response and apoptosis in renal tissue. This is mediated, at least partly, by modulation of the Nrf2/HO-1 axis.