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

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.

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.

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.

The administration of intrapleural sericin does not cause neurotoxicity in rats and can be safely used in pleurodesis procedures.