Is intrapleural sericin administration toxic to the nervous system of rats?

Background: Sericin is a natural, macromolecular, adhesive protein that is derived from the cocoons of silkworm. There has been no study to date in literature evaluating the potential for neurotoxicity associated with sericin pleurodesis. Methods: Adult, male, Wistar-Albino rats aged 12-week-old, weighing 211-256 gr (n=22) were divided randomly into two groups, each comprising 11 rats. A left thoracotomy was performed following intramuscular anesthesia. The A group was administrated sericin 30 mg and B group constituted by sham thoracotomy group. The rats were fed ad-libitum, all were sacrificed on day 13. The brain and cerebellum were excised en-bloc; T9-L3 segment was excised, and a sampling was made from sciatic nerve. Results: A subarachnoid hemorrhage was observed in the brain specimens of four rats (36.4%) in the control group and six rats (54.5%) in the sericin group (p=0.416). A capillary hemorrhage in the cerebellum was observed in six rats (54.5%) in the control group and in one rat (9.1%) in the sericin group (p<0,.05; p=0.024). A hemorrhage was observed in the central canal in three rats (27.3%) in the control group, whereas no hemorrhage was observed in the sericin group (p=0.082). Congestion in the fibers of the sciatic nerve was observed in five rats (45.5%) in the control group and in seven rats (63.6%) in the sericin group (p=0.416). The observation of capillary hemorrhage in the cerebellar specimens was significantly more common in the control group. Conclusion: The administration of intrapleural sericin does not cause neurotoxicity in rats and can be safely used in pleurodesis procedures.