Objective  To explore the feasibility of pigment epithelium-derived factor(PEDF) in human serum exosomes as an early biomarker of n-hexane-induced neurotoxicity.

  Methods  A total of 28 cases of occupational chronic n-hexane poisoning were selected as the case group. They were matched by age and gender, and 56 workers who were occupationally exposed to n-hexane without peripheral neurotoxicity symptoms were selected as the exposure group. And 56 workers who were not exposed to organic solvents such as n-hexane and did not have peripheral neurological damage symptoms were selected as the control group. Elbow venous blood was collected, and PEDF levels in serum exosomes were measured.Neuromyography was performed on the case group. Differences of PEDF levels in the case, the exposure and the control groups were analyzed by ANOVA, and Pearson correlation was used to analyze the correlation between PEDF and neuromyography-related indices in the case group.

  Results  The differences of PEDF levels in serum exosomes among the case, the exposure, and the control groups were statistically significant(P < 0.05), and the PEDF levels in serum exosomes in the case group were higher than those in the exposure group(P < 0.05), and the PEDF levels in the exposure group were higher than those in the control group(P < 0.05). In addition, the correlation analysis showed that PEDF levels in serum exosomes in the case group were positively correlated with the distal lower limb motor latency of the common peroneal nerve(r = 0.62, P < 0.01), and negatively correlated with the motor nerve conduction velocity of the common peroneal nerve(r = -0.70, P < 0.01), the action potential amplitude of the sensory nerves of the lower limb(r = -0.61, P = 0.001), the sensory nerve conduction velocity(r = -0.61, P = 0.001), and sensory nerve conduction velocity in the median nerve(r = -0.53, P = 0.004).

  Conclusions  PEDF in serum exosomes may serve as a potential early biomarker of n-Hexane-induced neurotoxicity.